You can make the master branch up-to-date using the following command. The git-pull command fetches from another local branch or integrates with another repository.
git pull origin master
The command will pull changes from the origin remote (URL of remote to fetch from), master branch and merge the changes to local checked-out branch.
The origin master is a cached copy of the last pulled from the origin.
Git pull is a combination of git fetch (fetches new commits from the remote repository) and git merge (integrates new commits into local branch).
Git pull merges the local branch with the remote branch by default.