I’m always struggeling deleting remote GIT branches from the command line (in my case PowerShell). Deleting the local branch is a no-brainer:

    git branch -d branchName

If you’ve to force deletion (which GIT will tell you via git status) you can use -D parameter.

Deleting the corresponding remote branch is done via a git push command. In detail:

git push --delete origin branchName

Hope that helps.