If you Google search "collaboration software", you'll find a bunch of options.
For chatting that can include multiple people in the same channel, there's Slack, Microsoft Teams, Discord, Google Groups, and that's just the one's I've used. There are are far more options out there. These also allow you to send files to other people. Some of them let you have a file storage outside of the chat feature.
If you need the ability to store lots of files for individual modification, there's Dropbox, OneDrive, Google Drive, and again, these are just the one's I've used. These tend to be unversioned storage. If you need to keep track of older versions of files, such as for software code, then you'll be looking for repositories like GitHub, BitBucket, or Team Foundation Server (now Azure DevOps).
If you need something where multiple people can be modifying the same file at the same time, Google Drive does that decently. It also has all the "normaly" file formats, such as spreadsheets, regular documents, PowerPoint presentation style software, and many more.
I haven't used any free website hosting for well over a decade, so I can't recommend anything for a wiki, but it wouldn't surprise me if Google had something that could be used for something like that. If you need something more robust, you can buy a domain and hosting service from GoDaddy, BlueHost, HostGator, Wix, 1&1, SquareSpace, or 1000 other places. Many of them have price reductions for non-profit organizations, if you are listed with the IRS. Some have easy to use drag-n-drop website builders to use, others host Wordpress, Drupal, or other easy to use site builders, which tend to include plug-ins for forums and wikis.
For a comprehensive option, Google shows up across most, if not all, of these categories.
There are far more options than I've listed, or can list. Except for the website hosting services, most of the options I've listed are free. They may have paid options, but the base software/service should be free to use. Some of the paid versions are based on how much you use it and others are based on how many collaborators you are working with. Definitely do your research to make sure it's the correct software and price for your needs.
Even though you don't expect to write scholarly papers, it wouldn't hurt to keep yourself open to that option, as well as other things you don't expect to do at the moment. You may end up doing a wider variety of collaboration than you expect. And when you need to collate that info into a paper on an individual basis, it doesn't hurt to have all of your work in one workspace.
Speaking of workspaces, using an online system will not only make things easier for your members to move information around, but it also serves as a backup to prevent anyone from losing all the data when their laptop or other device fails.
Hopefully this answers a few questions that underlie your stated one.
I'm not affiliated with any of these companies or pieces of software. I've simply used them or come across them in my personal or professional capacities.