If you happen to be on macOS, the Preview app does an absurd number of things to PDFs, and it does it well. To be honest I'm always surprised it isn't highlighted more by Apple, it's a great tool that pretty much always just works. You can split files, join them, rotate, add signatures, drawings, annotations, redact sections, etc. The feature list is long, especially considering that by the name of the application you'd think it could just preview files, not edit them.