Place holder text is to large

Before you fill with placeholder text, check your Paragraph Styles, Character Styles, and Control Panel. If you set character attributes with nothing selected, they become the defaults for the document. It looks like you have done that here.

If you resize placeholder text after you have filled a frame with it, it does not expand. You have to do it again.

Put your Type tool in the text and show a picture of the Control panel.

Make your own placeholder text:

Write your text, you would like to have to work as the placeholder in InDesign. Export it as "placeholder.txt" and save it at the very same place where InDesing App is found. (If you have other languages too, save it as txt file with the expression of that language at the same place like in German Platzhalter.txt.

I recommend to save it out from InDesign as this is the only way to be sure that you use the same decoding as InDesign on your computer would decode. There are several differences with extended characters and symbols, which would result in different letters, if the file would be saved in different programs like Word. This might not be so problematic in English, but it causes problems with languages like Castellano or German, where you find a lot of extended characters in any text like ñÑéÉóÓ äöüÄÖÜß çåÇÅ and many others.

Picture below is a screenshot of the issue and the font size is set to 12.

Reposting the screen shot with the Control panel and the rulers visible and the text cursor in the text will help us.

Is there a character style or object style applied?

There must be something wrong with your numbers.

You say, page size is 8.25" x 10.75" and font size 12 pt?

Then it should look something like this:

Try placing your text with the Shift key pressed and the text will reflow automatically. Then you can adjust the text as you want.