How do I customize the Attachment page?

Hi Marty,

Any chance you can link us to the site in question?

You can use the private information field.
https://docs.generatepress.com/article/using-the-premium-support-forum/#private-information

Let me know :)

I am working in LOCAL

The attachment page is handled by WordPress, the theme has no control over it.

I would recommend checking with WP support.

OK, disappointing answer. Will I have to make a Child Theme to do this? Is making a Child Theme in GeneratePress the same as making a Child Theme in WordPress?

Here's the guide on how to create a child theme with GP:
https://docs.generatepress.com/article/using-child-theme/

I haven't tried, but I think block element - content template should work. You can assign it to mediaas location:
https://docs.generatepress.com/article/block-element-content-template/

You can use the dynamic content block (with GP logo as icon) as the media content eg. images.