Hi, @wealthy.
Glad you reached out.
You can enable the Donor Comments functionality by navigating to donations > all forms > click to edit your form > form fields > Donor Comments. You can enable it on a per-form basis or globally too.
Regarding adding a section where you explain what the comment field is for, you need to insert text using WP hooks to reposition it. It’s complicated.
However, if you use the visual builder forms, our v3 forms, you can add the comments section and explain it. See it here: https://imgur.com/a/ekf7gMZ.
Please let us know if you have further questions or need additional assistance!