In very basic terms, could someone explain CRMs, how to begin learning about them, and if they would at all be or use to me?

So like many IT/newer computer related fields I don’t really understand CRMs. From what I do get, they seem to be software services to automate and improve overall business efficiency. Tracking customer data, interactions, potential leads etc to then be more manageable & easier to access. Is this correct? Also it just seems their are so many different things they could potentially do and different platforms for a variety of needs that I’m confused what I’m even talking about here. I’ve tried to read up somewhat on my own.

The reason I am interested in this is because for one thing I’m considering going to school and am looking into different fields related to business. Aside from that i sell products online on e-commerce sites (ebay fb etc) and run some small side projects. I’ve wanted to find a way to promote, scale, and become more efficient at these things increase business Etc. Was looking into “ClickFunnels” FB/IG ads, and others but ran into issues/didn’t hear great things and have been looking for alternative since to try and do this. Would a CRM be of use? Where do I start?

Thank you for all the help everyone! Sorry I know that’s probably confusing and vague.