I'm still just learning and have no formal experience in working with developer teams but will offer my own experience.
When I first started learning I also wasn't sure how to document my progress. In the beginning, I was just bookmarking everything in separate folders in Google Chrome. Eventually I thought I would try blogging but that didn't work out so I stopped.
Fast forward to last year, I discovered 100 days of code. The way they had you essentially journal each day was very clever, and it was all done on GitHub. Unfortunately I did not complete the 100 days but I still documented many days. I hope to restart the hundred days soon.
Fast forward to present time, I now have a devblog on hashnode and recently signed up for Notion. Both of these offer very intuitive ways to document, journal and share my progress. While everything on notion will most likely stay private unless I share templates, I'll be able to share my progress as well as establish a personal website dedicated to my developer journey on hashnode.
If you don't have a Devblog yet, I highly recommend it. I also recommend notion.