Git submodule push when it is a GitHub library?

Question

I added a GitHub-based library as a submodule and modified it. I need to share the modification with my teammates.

• I won't be able to push it to submodule's GitHub origin, would I?
• How do I share the modification?
• I'm not supposed to modify submodules which I get from GitHub?

Answer 1

• I won't be able to push it to submodule's GitHub origin, would I?

No: you need to fork that GitHub project first, and add that fork as a submodule.
(or change the current submodule url by the one of your fork )

• How do I share the modification?

Once you have added your fork as a submodule, you will be able to push modification to its upstream repo.

• I'm not supposed to modify submodules which I get from GitHub?

Submodule or not, you cannot modify GitHub repos you are not the owner (or a declared collaborator) of.