Customize newsletter confirmation email

Hi @power pops, welcome to the community!
Yes you can customize the double-optin confirmation emails.  Those emails can be customized in the account’s default consent page settings here:

• Settings → Other → Consent pages → Email Confirmation

And, if you have a List specific consent page settings enabled, then you go to:

• List & Segments →  (“Your List Name”) → Subscribe & preference pages → Email Confirmation.

There, you can custom the email by adding in additional blocks of images or text.  Here’s an example:

Hope that helps!