This post assumes you’ve already read Generating a PGP key.
I’ll be using my key for these examples but you’ll want to replace
95535225B55B5A9F39E29F5EDAB85EABB6014D3F with your own in the commands.
For adding it to github run the following and copy the whole output.
gpg --armor --export 95535225B55B5A9F39E29F5EDAB85EABB6014D3F
That will generate a very long wall of text encapsulated by
-----BEGIN PGP PUBLIC KEY BLOCK----- -----END PGP PUBLIC KEY BLOCK-----
Then navigate to https://github.com/settings/keys and paste the entire body of the output into the “New GPG Key” text box.