Last night I dreamed of a Pixar story, so this morning out of idle curiosity I thought I'd Google how to write for Pixar. 
Bottom line is that you'll need to be resident in the USA, but also almost certainly have a good track record of screen-writing behind you, and you'd probably also need to have experience writing for Disney as well.
However, I found an interesting guide to writing for Disney online, just in case anyone here ever gets any serious ideas about screenwriting, perhaps even for Disney/Pixar.
www.writingbeginner.com
In the meantime - and I think we've posted this before - here are 22 story tips from Pixar on what makes a good story:
nofilmschool.com
Bottom line is that you'll need to be resident in the USA, but also almost certainly have a good track record of screen-writing behind you, and you'd probably also need to have experience writing for Disney as well.
However, I found an interesting guide to writing for Disney online, just in case anyone here ever gets any serious ideas about screenwriting, perhaps even for Disney/Pixar.

How To Become a Writer for Disney [Ultimate Insider Guide] - Writing Beginner
How To Become a Writer for Disney [The Ultimate Insider Guide] ~ Disney is a billion-dollar global company, so 99% of writers would jump at the chance to write for them. I know I would—without even blinking. If you would, too, then you’re in luck. This post is your ultimate blueprint to writing...

In the meantime - and I think we've posted this before - here are 22 story tips from Pixar on what makes a good story:

22 Tips on the Pixar Storytelling Formula
The Pixar storytelling formula has been used over and over again by the company to create emotional and successful screenplays. How does it work?