Each Git commit is uniquely identified by a hash e.g., d670460b4b4aece5915caf5c68d12f560a9fe3e4. As you can imagine, using such an identifier is not very convenient for our day-to-day use. As a solution, Git allows adding a more human-readable tag to a commit e.g., v1.0-beta.
Here's how you can tag a commit in a local repo:
Right-click on the commit (in the graphical revision graph) you want to tag and choose Tag….
Specify the tag name e.g. v1.0 and click Add Tag.
The added tag will appear in the revision graph view.
To add a tag to the current commit as v1.0:
$ git tag v1.0
To view tags:
$ git tag
To learn how to add a tag to a past commit, go to the ‘Git Basics – Tagging’ page of the git-scm book and refer the ‘Tagging Later’ section.
After adding a tag to a commit, you can use the tag to refer to that commit, as an alternative to using the hash.
Annotated vs Lightweight Tags: The Git tags explained above are known as lightweight tags. There is another type of Git tags called annotated tags. See git-scm.com/book for more info.
Tags are different from commit messages, in purpose and in form. A commit message is a description of the commit that is part of the commit itself. A tags is a short name for a commit, which exists as a separate entity that points to a commit.