Which of my Canon lenses can I use on my full-frame camera?
The first letters of the lens name will tell you the type of lens it is. You will probably be able to keep and use many of your existing lenses when switching to a full-frame camera, but there are a few things to bear in mind.
EF-S lenses can be used with full-frame mirrorless EOS R System cameras with an EF-EOS R adapter. However, the resolution you get from your camera will be reduced, as the lens won't cover the full-frame sensor. I would therefore look to replace EF-S lenses with their RF equivalents if moving to the full-frame EOS R System. EF-S lenses will not work with Canon full-frame DSLRs, so if you prefer the feel of a DSLR camera and choose that path then you will have to replace them with EF lenses.
EF-M lenses are designed to be used with EOS M series cameras only, so if you change to full-frame you will need to buy EF or RF lenses to go with your new camera body.
EF lenses are compatible with all Canon full-frame cameras – with an EOS R System camera, you will need an EF-EOS R adapter, but there will be no loss of quality or functionality. EF lenses will also work almost exactly as they do on your current camera, the only difference being that your EF lenses will appear wider than on an APS-C camera, as the APS-C format introduces a 1.6x crop to the image. If you like to use a 50mm lens on an APS-C camera for portraits, then you might want to consider using an 85mm lens on a new full-frame camera in order to achieve the same framing.