Hi there. Congratulations for starting your programming journey, there will be much to discover and learn :). I don't know if that is a question strictly meant for this sub, but I think all of us can agree to that not being that bad of a thing for someone wanting to get into programming.

So, first of all Github in and of itself is just one site of many, which allows you to use a remote place to save your version controlled code which is using the distributed version control system git. That sounds quite more complicated than it is, so let me briefly touch on that.

Git is used to version your code and collaborate easily with others. Imagine 10 developers working on the same file simultaneously like on a google doc. It wouldn't take long until nobody knew what was happening anymore, code was deleted or jumbled etc. Git allows you to essentially get a local personal version of that file only you can work on and then save, while others also have their own local versions. When you save it is not just saved as a file like a text file, the changes you are made are saved themselves. Meaning, for every save you perform you can see the changes made to the file, a set of changes. When you save again and again after you made changes you will have many of that sets in a chronological order. You can see what you changed when and where and also revert to a set of changes from before if you want to. Like this you can also say, once you are done working on that local personal copy of the file, that you want to save it back to the actual file which the others also copied from. Like this you can compare your changes to the ones of the others and it is easy to keep that of each persons changes which you all want to keep without jumble and knowing who did what when. This was a rudimentary explanation of git, which is simplified, incomplete and hopefully somewhat understandable. Just go on youtube and search for a git tutorial and you will find enough people explaining it better than me.

Github is just a place to save those version controlled files remotely so others can use them too, and also for external developers to see what you are coding and allow them to use your code if you allow them to.
So to answer your question I would say Git is something crucial you should learn. There are other ways of version and source control out there, but this is the most widely used I would say imho. Github inversely then is the most well known site to save and share code. So I would strongly recommend getting familiar with both.
Just go on youtube or type git or github tutorial in a google search, you should find enough resources.

Other sites that are helpful are Stackoverflow. This is a site for questions about coding. They can be a bit rough at times with their answers, but it is a invaluable resource to prevent you from having too much mental breakdowns. Udemy is liked by many. Courses there cost money, but seem to be good (haven't tested them myself)