How do I convert an existing Google account to G Suite?

I have an existing account using an e-mail at a domain I control (e.g., orome@my-domain.com) and would like to convert that account to a G Suite account. I'm unclear on the correct steps to do that while still preserving the data and credentials associated with my orome@my-domain.com account. Is there a way to accomplish this, and if so what are the steps involved?