Tags are refs that point to specific points in Git history. Tagging is generally used to capture a point in history that is used for a marked version release (i.e. v1.0.1). A tag is like a branch that doesn’t change. Unlike branches, tags, after being created, have no further history of commits.

For a bit more in-depth discussion see https://www.atlassian.com/git/tutorials/inspecting-a-repository/git-tag.

• Listing your tags —

  # to list all of your tags
  $ git tag 
  

  # to search for a specific string in the tag list
  $ git tag -l <search string>
  

• Creating tags —

  # Annotated Tag: annotated tags store extra meta data 
  # such as: the tagger name, email, date, tagging message etc.
  # they can also be signed and verified
  $ git tag -a <tag> -m <message>
  

  # Lightweight Tag 
  $ git tag <tag> 
  

  # Tagging at a previous commit  
  $ git tag -a <tag> <commit checksum (or part of it)> 
  

• Checking out tags —

  $ git checkout <tag name>
  

  Note: This puts the repository in a detached HEAD state. This means any changes made will not update the tag. They will create a new detached commit. This new detached commit will not be part of any branch and will only be reachable directly by the commits’ SHA hash. Therefore it is a best practice to create a new branch anytime you're making changes in a detached HEAD state.

• Sharing/transferring tags to the remote —

  By default, the git push command doesn’t transfer tags to remote servers. You will have to explicitly push tags to a shared server after you have created them. This process is just like sharing remote branches —

  $ git push <remote name> <tag name> 
  
  # If you have a lot of tags that you want to push up at once use 
  $ git push <remote name> --tags.
  

• Deleting tags —

  # From your local machine 
  $ git tag -d <tag name>
  

  # From the remote repository 
  $ git push <remote name> --delete <tag name>