If you haven’t already, check out https://choosealicense.com/licenses/ . This gives a broad overview of the common open source licenses. And if you’re just starting out, one of the first things you’ll want to learn is that the licenses fall into either a permissive or copyleft category. You’ll want to make sure you understand the difference between those broad categories.

Shortly, permissive have less to no strings attached to use their code, and copyleft requires you to retain the same licensing terms meaning if you publish under GPLv3 then someone using/ modifying your code needs to also publish under GPLv3. Copyleft licenses ensure that open source code stays open source.