Are we able to customize what the email notification will look like?

Second: Are we able to customize what the email notification will look like in terms of verbiage once the client signs up and pays through your forms?

Yes, this also doable. This applies to both NOTIFICATIONS (the emails you receive) and AUTORESPONDERS (the emails your customers receive).

Have a look at the guide I linked below and give it a spin.

Complete guide: How-to-Edit-the-Email-Template-for-Notifications-and-Autoresponders