what are some *free* screen recording software for windows? I want to record videos and turn them into GIFs later. Any suggestions?
For windows 10 you can use The Game Bar functionality. Originally used to capture screen vids for showing off video games you can use it to capture all sorts of screen videos: https://support.microsoft.com/en-us/help/17188/windows-10-record-clips-of-pc-games
OBS is mainly used for streaming, but can write directly to files (for youtube uploads, etc.).
LICEcap is quite good. I have used it when I was on Windows and I remember I liked it. https://www.cockos.com/licecap/
You can record your screen and save as gifs with https://www.getcloudapp.com/