Normally, you’ll have a .gitignore file that defines what should not go into a git repository. If you find that there is a file or two that is ignored that you really need in the repository (e.g. a DLL dependency in a BIN folder for some legacy application that doesn’t do NuGet, or other package management) then you need a way to force that into Git.
The command you need is this:
git add --force <filename>
<filename> with the file that you need to force in. This will force stage the file ready for your next commit.
You can also use . in place of a file name to force in an entire directory, or you can use wild cards to determine what is staged.
Afterwards you can use
to see that it has been staged.