Students can choose teammates from a list of other students in your section when working together (pair programming) in Code Studio. Teachers can track both team progress and individual student progress.
We published a blog post with more background and a brief walkthrough (via pictures and animated .gifs) on pair programming here:
Students will need to be in the same section for them to select partners for pair programming. All sections (regardless of assigned course) by default support pair programming - either word/picture-based, or email-based. Note that any pairing of students is not permanent by any means. Students will be un-paired upon signing out of Code Studio every time, and can choose different partners upon signing in again.
For word- or picture-based sections, students will see an checkbox option upon first visiting their section's join page (studio.code.org/sections/ABCDEF for example). For email-based sections, students can find an option for selecting a partner upon clicking their name in the top-right corner of any Code Studio page, and selecting 'pair programming.'
A student that selects other partners will be labeled as the 'logged in' person within your 'view progress' page when reviewing their progress, while other partnered students will read as 'partners'. Any progress made by the logged in person (as in, green bubbles of progress indicated completed puzzles) will reflect upon the partners' sides as well.