Hi there, Carly! I love this idea, and I think it would give a lot of people a great chance to contribute to the site.
Currently, I don't think there is a way to directly contribute to the site's guides but you can feel free to post your own on the respective boards where they could belong! If you really want the guide to appear in the official section, though, I would suggest posting it in the Site Suggestions board. (Not too sure if that's the right way to do it though–let's wait for a modmin's response on that )
There was a Special Projects Team (that may still be in existence, I'm not sure) that had a sole purpose of creating new guides, as well as updating older ones. This team consisted of Community Members, while I do like the idea of letting the Community get involved more, we also have to think of logistics. There is of course, always the off chance of incorrect information and spam, but seeing as everything is read over and such before being uploaded to the live site, this is easily preventable - unless you're suggesting something like a Wiki (which I can't don't would be approved for the reasons listed above). There's also only so many guides that can be created.
I suppose I was just wondering if there was a way I could personally submit a guide to someone to be reviewed and have it posted on the site. Like, I also like the idea of everyone being able to contribute, but I meant more of an official approach to it. If that makes sense.
I don't know about you personally submitting one, I'd PT a Modmin and ask.
"Like, I also like the idea of everyone being able to contribute, but I meant more of an official approach to it. If that makes sense."
The idea of everyone contributing is the idea behind the Game Guides SPT. It's members who were willing to help update/create guides. I believe in the last the team was opened to reapply yearly, so anyone who wanted to apply could.
Something that could work is possibly creating a new board, and members could post their guides as well as get feeback from other members. Then, if approved by staff could be uploaded to the site.