How can to save username and password for Git in local machine

This method saves the credentials in plaintext on your PC's disk. Everyone on your computer can access it, e.g. malicious NPM modules.

Run

git config --global credential.helper store

then

git 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.