The easiest way to use a custom domain is to go into your email service provider and change the "From" address to your desired email.

In order to receive emails at your desired email, we suggest that you setup an "email forwarder" so that any email sent to Nancy@NancyDrew.com will appear in at NancyD@Gmail.com. That way, if anyone responds to your newsletters, you'll get their reply in your existing gmail inbox.

Mailerlite will let you send from Nancy@NancyDrew.com, however, if you want the ability to respond to individual emails via Nancy@NancyDrew.com (as opposed to NancyD@Gmail.com), Google charges $5/mo to send from your own domain. Most of our clients opt not to do this, because they do not send a lot of personal emails from a custom domain.