index.php showing up in permalinks

Hello

I’m noticing for the first time, all the pages I’m creating have “index.php” in the permalinks.

For example, I’m working on this page:
vitalthrive.us/index.php/about/

So when I created this about page, instead of it saying
vitalthrive.us/about, it reads, “vitalthrive.us/index.php/about/”

I feel confused and need understanding please.

I have gone into settings>permalinks and tried to change the”Common Settings” to “Plain” and then the page didn’t show.

I feel curious and would like to understand, how can I create pages that have just a normal permalink and why is the “index.php” is showing up in there?

Thank you WP community!