I use Github generated release notes based on Pull Request bodies and this is more than sufficient for my dev team.
I think have a small app in my different internal web application called `releases` (a Django app) that has a simple model called Release. I hand write the release notes, copy and paste the version number, and select date for each release (sometimes I'll batch add them if I get behind).
But I had write them with my audience in mind (business system users - who care about specific bugs or features; i leave out any internal things that wouldn't be of interest).
At the footer, or a small indicator in side bar, I display the version number that was created through our automated release process (Github Release triggers a release and the tag that is the version number gets set as an env var in my Docker image). Clicking that takes the user to a /release-notes/ page that has a descending order list of the notes that I hand author in the Django admin.
Pretty low tech but I find I like to be able to hand author the notes with the user's in mind.