Hi Tom,
Thanks for writing to us.
In case if you want to show text on hover on the posts featured image it would require custom development. I would recommend you to contact a developer who can assist you with your concern or you can avail of our service called One, where the customization questions are answered.
Please note that we don’t provide custom development support. It is out of the support scope.
In case if you want to display text on Image hover (Not Post Featured image) you can show text on hover over an image using Card element. Add same background image for normal and hover view from and back settings.
Then remove the text from Front Content settings
Now disable the button text from Back Button settings and set font size 0 for the button.
Then set Flip time 0 from Interaction & Duration settings.
Here is documentation of the card element.
Thanks