Here we need to see the difference between
Origin: This is the name of a remote. A remote in Git is a common repository that all team members use to exchange their changes. In most cases, this will be an origin.
Master: This is a branch name where we first initiate git and then we use to make commits.
And the changes in the master can pull/push into a remote.
origin/master: This is a remote branch, which has a local branch named master on a remote named origin.
I hope you got the difference between origin master and origin/master.