How to add branch? to a friend's warehouse in the form of pull requests

I downloaded master
from fork + clone and then created a branch via master . What should I do to submit this branch directly to my friend"s warehouse, and master can I switch branches by switch branches/tags on github ?
instead of overwriting the master branch?

Mar.10,2021

create pull request in a friend's warehouse, submit the branch you want to submit, and then let the friend handle it

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