It syncs over wifi. There’s a windows/mac/ios app that you can drop files into and they show up on your reMarkable.

There’s even a chrome extension that lets you click a button and the page shows up on the tablet in epub form (which unfortunately doesn’t do images). You have to print-to-pdf then dump into the app to get a webpage with images onto the tablet. That part’s kind of annoying, but many articles work just fine as epub.

drag and drop on the app and they sync.