OBS is a little complicated, some output settings to pay attention to to get the file type you want (defaults to other than MP4).
Then you have to configure your inputs, i.e. add your Display and sound.
It's very cool, and records locally, which is great.
There's one called Techsmith / Jing / Snagit:
TechSmith Capture is a simple, free way to create basic screenshots and screen recordings and share them with others.
www.techsmith.com
It has some neat tools for selecting the screen area you want to record.
The downside with this and many screen recorders is they upload to the cloud.
Then you have to go find your video and download it to work with it locally.
So, if you want local files just use OBS.
And honorable mention goes to the Windows Game Bar (windows key + G). If you're in Windows that might be the easiest.