<key_id> will be signed by <your_key_id>.

Importing the key from server

[gpg2 –recv-keys <key_id>]{.title-ref}

Verify fingerprint

[gpg2 –fingerprint <key_id>]{.title-ref}

Signing the key

[gpg2 –sign-key <key_id>]{.title-ref}

Sending the key

[gpg2 –armor –output <key_id>.signed_by.<your_key_id>.asc –export <key_id>]{.title-ref}

<key_id>.signed_by.<your_key_id>.asc can be send by email or shared using any file sharing service.

Importing the signed key

[gpg2 –import <key_id>.signed_by.<your_key_id>.asc]{.title-ref}

Exporting the signed key to server

[gpg2 –send-keys <key_id>]{.title-ref}

Other useful links

What is key signing Debian Key Signing