Received email of expiration notice for using my email

Great question @user_ofqtr0 The link: https://www.xfinity.com/support/articles/yahoo-email-migration-overview will go over how to upgrade your Comcast email experience to Yahoo Mail. 

@user_ofqtr0 

What do I need to do to make sure I can still use email

If you've been using a third party email app you need to periodically log in to webmail.