Hi Abigail,
There unfortunately is not a filter at this time 🙁
But you can indeed change this quite easily with a template override. First, if you haven’t already, check out the methods for Events Calendar / EDD Tickets template overrides here in our Themer’s Guide → https://theeventscalendar.com/knowledgebase/themers-guide/
Using those methods, the file in question for this change is located here in your EDD Tickets plugin files:
/src/views/eddtickets/tickets.php
There, you’ll see this:
<h2 class="tribe-events-tickets-title"><?php esc_html_e( 'Tickets', 'tribe-eddtickets' );?></h2>
If you just replace that with “Enroll Now” or anything else you’d like, and leave the rest of the file like the original, you should be good to go.
<h2 class="tribe-events-tickets-title">Enroll Now</h2>
Let us know if this helps!
Cheers,
George