permalinks and static pages

I’m trying to understand permalinks and static pages and have visited the codex, but I don’t think it’s clear enough – it’s almost expect that you understand what is being done, rather than explaining what is being done?

I want my site to display the about link as https://sekhu.net/wp/about If I enter that URI it actually displays the page, at the top however it displays as index.php?id=x why is this?

I did update the permalinks for the links, about and archives. If I click on archives, it will displays the same URI as above with a different id, clicking on an archive month will display the masked URI of archives/month/day/year.

Can someone explain the understanding behind this better than the codex and how it works with static pages, and basically how to make it display as such. I know my files are protected with the id=x but a the same time, would prefer the links to be “cleaner”

Thank you