Once you're logged in, tap on your avatar on the top right of the screen. Tap edit profile from the drop down menu. Note: you can't edit your email or password in the app, only on web at Audiomack.com.
From the edit profile page, select "Update Email." Enter your new email and your existing password to update successfully.
Note: You can only edit your email address on the Audiomack website, not on the app.