What I normally do is type “Click Here” after the first character, then delete the URL.
Here’s my 3 step process:

That’s what table styles (and cell styles) is for, yes? (But no, you cannot find/change tables.)

Um. Well, it is a form field. If you have other form fields that get submitted, then these text fields would get submitted, too, I guess. But if it’s just a PDF with interactivity, then sure, you can have form fields and not give them any way to submit the form. Fun idea.

Tiffany: Your system means it is probably something on that account… typically something in the original account’s Library folder. This is always a pain and difficult to troubleshoot. Could be fonts, or some other Adobe preference, or… it’s hard to know. But if you have rebuilt your preferences, then it’s probably not specifically InDesign.

GREP cannot search for location on a typeset line, so I do not think that is possible.

Have you used the Indic languages script to ensure you can typeset in Tamil properly?