how do I do a fresh os install without including my personal data

If you want to effectively erase everything on that Mac and return it to its original, "out of the box" state, then follow these instructions:

What to do before you sell, give away, or trade in your Mac - Apple Support

Just be sure that's what you really want to do, because I may be assuming you want none of your personal data (or anyone else's) to remain on that Mac. It will be completely erased and a new copy of macOS will be installed.

👍

Thanks for confirming your intent.

You can stop after Step 7. No need to reinstall macOS if it's just going to get recycled. Even if someone else wants to repurpose it, the time-consuming step of reinstalling macOS can be performed later.

johnmoxl wrote:

how do I do a fresh os install without including my personal data

Fresh install of what on what and what personal data is it asking for?

https://discussions.apple.com/docs/DOC-5931