After keys have been generated, we need to ensure that we spread our public key far and wide. It can be attached to every email we send to others, but the problem is, it becomes a big pain to do every time.
The easiest way to spread the public key far and wide is to upload it to a key server. Key servers hold millions of public keys of many GPG / PGP users like you and me. Whenever anyone wants to add your public key to their key ring, they just need to import it from the key server. You can modify your email message signature to indicate to people on which key server they can locate your public key.
First of all, find your key ID. Refer this link to know how.
To send the key to a key server, open a terminal window in Ubuntu and at the command prompt, enter:
gpg --keyserver pgp.mit.edu --send-keys 3949C65A
The key with ID 3949C65A will be sent to the key server at pgp.mit.edu. Keys once submitted cannot be deleted. They can only be revoked.
Once done, you can visit http://pgp.mit.edu and verify that your key was uploaded onto the server.