Firstly before trying to know anything writing a movie script you have to understand what writting is all about

What is writting? 

Writting can simply be define as composing a marks and sign that represent the utterance of any language or moral activity.

Since writting has been define as the compost of marks and sign which represent a language utterance, what does writting of screenplay mean?

A screenplay/script can be define as a written work by screenwriters (or an unanimous) for film making, television show, video games and others it's a written dialogue with description to be shooted and produced

When writting a screenplay you have to include this elements

  1. Scene heading

Scene heading is the first thing that appears in every screenplay,it describes where and time movie script is been shooted, every screenplay must include a scene heading it is compusery because it describes how and where a screenplay are been shooted, without including a scene heading in your movie script, directors and script supervisor will find it difficult to understand your script,it describes weithwe a scene is been shooted;morning, afternoon, evening; every screenplay must have either EXT or INT
EXT: are been used when a movie script is been shooted outside a structure e.g football field, road, school assembly ground and others
INT: are been used when a movie is been shooted inside a structure e.g kitchen, office, bedroom, inside a car, inside an aircraft and others.
 In every scene their must be a scene heading because it has a very special role it describes the actual moment a scene is been shooted and with that, the director and script supervisor will understand your script better.scene heading are been written in this way;
EXT: FIELD - MORNING
                 OR
INT: CHARLES OFFICE - AFTERNOON
also know that scene heading are been written at the left hand side of a scene. we

2. Action

An action is the second element of screenplay which describes what is going on in a scene,after writing down your scene heading action follows Immediately,like I said action describes what a character do or what a character will be doing in a scene, it's a small summary of what  will happen in a particular scene, so without writting an action in your screenplay it's quiet difficult for directors to understand your script, that means every movie script must have an action description, without it your script looks like a novel so you have to include action in every scene on your screenplay
Example.                                                                      
Jacob and  saney sitting in a bar drinking alcohol while discussing"
So in summary you will understand that action describes what takes place in every scene

3. character

Character is also needed in a screenplay,they are  representing  different types of role or you can say character are names of participants in a scene so after writing down an action then character carries out what happens in every scene so character is also necessary in a movie script because without including a character automatically you are writing a novel/tale not a movie script.characters are those people or animations  you see with their different roles according to the movies.a scene can have only a character or have about twenty or more characters in every scene it depends on the kind of script you're writing,note character are very important in a movie script
Example
Actors and actresses are example of character,bec because they represent a special role.in animations movie;Tom and Jerry 
So you can see that character are necessary in a movie script.

4. parenthical

This is another important thing in a movie script it represent motion or reaction of a character, when the character is crying, smiling, angry not responding or gazing at something e.t.c it helps the director understand what happens into my a screenplay and they're written under brackets behind the character name but very important, it also helps you screenplay looks interesting, when you are writing a script and always include and always include parenthical your script looks amazing and interesting to read because it helps a character to know what to do so a screenplay need to have parenthical in some areas of your scene

5. dialogue

These are written words or it can be called what a says in scene.they are those conversations you here by one, two or three characters says it can be discussion it can also be a voice over in a scene so every scene with a character can have few dialogue.because it's necessary every screenplay must have not less than 10 dialogue
So dialogue is also important thing in a script
Example
"Where are you going?,come back here" and different types of conversation.just know that dialogue are those things a character says in a movie.

6. Transition

Transition is another important thing and also the last thing that appears in a scene.it describes how the scene ends either the scene ends in a dark mode or the scene is been cut to the next, but the most important thing is the type of transition to use in an ending of a scene because trying to end a night scene and jump into morning you have to know the suitable transition to use, secondly transition also helps directors and screenplay supervisors understand how a particular scene ends and how it starts

Examples of transition

We have  cut to, fade in,fade out.these are basic types of transition, cut to represent when a scene cut to the next,while  fade in are normally use when starting a fresh Act or in the morning while  fade out/dark are you to close a scene usually at the night, when trying to transit from night to morning we use fade out and then fade in. so these are basic transition

These six elements are important when writting a screenplay though we have others like; shot, text theme and others but these six I stated here are the basic important elements

How a screenplay looks like

People's frequently ask

How do I write a scene where a spirit/invisible person is talking?

Well,when writting a scene where an unknown person or someone speaks in his mind we use "v.o (voice over)" it describes that the person is not in the camera views so when writting a scene when someone speaks on his mind use v.o.

What tense are screenplay Writting on?

This is very important,scripts/screenplay are written in present tense because the are activity that are yet to be carried out so when writting a script always write in present tense but when writting a flashback we write in past tense in other for directors to understand it's a flashback so screenplay are written in present tense while flashback of a scene is written in past tense

How do I write a flashback?

When writting a flashback you have to end the scene where you are and then start another scene,at the transition write it a flashback so that the director will understand that you are writing a flashback and every action are written in past tense it also helps the director and other viewers understand your script

What is the difference between script and screenplay? 

This is another thing a writer need to understand, script are just written words,action, character and dialogue while screenplay contains the details how the script will be shooted both camera directions and exact place where the movie take place.

Where can I sell my script?

These are questions I normally received from people, firstly when you have a script and want to sell but don't have a source to start from,then consider selling them online.when selling your script online you have to know this things,firstly you have to copyright your work otherwise you might end up being scammed,then after copyrighting your script find a litter agent that will help you submit your script to all production companies, like Netflix, universal studios, Lucasfilm,20 century and others big production companies, you can't submit them by your self because they do not accept unsolicited script or find a screenplay Writting competition or feel free to submit your script to BBC studio but you have to know that BBC studio those not pay when you submit your script to them but you stands a chance to meet all Hollywood producers and film production companies accross the world,or register at MDB PRO or INKTIP PRO and start communicating with profprodu when you post a script on your page.

Which software can help me write a script?

If you wish to write a movie script thier are many types of script writting software but I prefer using "Celtix or fade in" because they are totally free of charge.apart from them we still have other apps like studio binder,
Final draft,WriterDuet and trelby.

Is script writting profitable?

Script writing is really profitable because it is another part of film production that is necessary in film making without a story/script their will be no movie to shoot.
This is another thing to know, screenwriter mostly face a common challenges, like stealing of stories, this is important to know, someone can still your story and then write it down in another form and luckily he might even sell it before you at this time your script has been profitable for another person, another thing you have to know is that the numbers of screenwriters are bigger than producers so new writer might not have an opportunity to sell their script on time.