There's a bunch of different resources that you can use to learn guitar online. Some of them are free and some of them are paid. The free ones are nice because you don't have to pay anything, but typically they don't have the same quality and depth as the paid ones do. Go figure, you get what you pay for.
I've used several paid ones over the years and feel like they were worth the price because they definitely helped improve my playing. The most popular guitar lesson websites
out there right now are probably GuitarTricks, Jamplay, and Fenderplay.
Guitar Tricks is about $20 per month and they have a wide range of lessons from beginner to advanced. They also cover a lot of genres. I think this is probably the easiest site to get started on if you haven't taken any online lessons before.
Jamplay is a little more expensive and they tend to have different styles of lessons than GT. I like Jamplay's metal and heavy music lessons that the other companies don't offer. This one isn't quite as intuitive as GT, but it has some more unique lessons.
Fenderplay is relatively new to the teaching world. I think they are about $10 per month. I tried them out because they were offering a free trial for a while. The thing that I liked most about their platform is that emphasize learning popular songs. They seem to have a large variety of different songs that you can learn which is fun.
Personally, I don't think you can go wrong with any of these websites. I think most of them have some kind of free trial that you can sign up for before you buy them. It's worth checking out to see if you like them before you sign up. Hope that helps!