Fix up email system so I can read emails off google interface

General information for the business: We sell coaching programs and supplements
Industry: Education
Description of support work: I am needing assistance with using my gmail account to read and respond to emails from a roundcube server that has been setup as a webmail account. So all I want to do is simply reply with marie@transformhc.com as my main email off a random setup gmail account based on connecting it with the webmail account.
Extra notes: I don't even know if this is possible!