A free template to help you write in screenplay form (Warner Brothers format) with Apple Pages, the free Apple productivity app.
The title page is pretty much self-explanatory: you can write your title, credit and add you contact details.
Then, start writing your screenplay using the Text tab to format your script:
The scene index will build up as you fill your script with scenes.
The template is set in Courier, the traditional screenplay font, but if you want it to look better, you should use Courier Prime, an open source font designed by Alan Dague-Greene for John August and Quote-Unquote Apps — you can download it here: https://quoteunquoteapps.com/courierprime.
(Click on the picture for details)
Warner Brothers screenplay template for Apple Pages