If you use free Gmail mail, but you also have your own personal domain with personal email, after a series of simple settings you will be able to send letters from your domain's email using your usual Gmail account.
How to do it?
Using the instructions on the link add your mailbox to Gmail account.
The process of adding is somewhat similar to setting up your email in an email client, with the difference that in this case, in addition to the username and password, we specify only an SMTP server without a POP server.
At the last step, a request comes to a domain mail with a request that must be confirmed by clicking on the link in the letter.
Please note, that this function only works for sending. If you also want to read the incoming letters of your domain mail in your Gmail account, you will also have to configure redirection from the domain email to your Gmail in cPanel or Direct Admin hosting control panel.