save username and password in Git?

This method saves the credentials in plaintext on your PC's disk. Everyone on your computer can access it, e.g. malicious NPM modules.
1- run in terminal
git config --global credential.helper store
2- then
get pull

provide a username and password and those details will then be remembered later. The credentials are stored in a file on the disk, with the disk permissions of "just user readable/writable" but still in plaintext.

If you want to change the password later

git pull

Will fail, because the password is incorrect, git then removes the offending user+password from the ~/.git-credentials file, so now re-run:

git pull

to provide a new password so it works as earlier.

Happy Coding