Earlier quoted context omitted.
Just type your code in the editor. And it offers auto complete suggestions. Sometimes it will complete the entire function based on the function name or a comment. Sometimes it'll just guess the function you want to write, without you typing anything at all. (Turns out a lot of code is rather predictable). By experience though it’s best to go line by line rather than accepting whole function autcompletes. For me, I f…
They have a limited trial or company memberships afaik. It costs 10$/month 100$/year for individual users.
EDIT: GitHub Copilot is free to use for verified students, teachers, and maintainers of popular open source projects