Lots of ways... sorry your question is too vague/imprecise
Also, depends on exactly which model camera as some have clean output via USB, some have clean output via HDMI, etc.
*IF* you have a relatively current camera, Canon's USB webcam driver may work, though on anything but latest cameras, using USB2.0, will be much lower resolution. With older cameras, common approach is using a HDMI capture card, but camera model specific as to whether you can get a clean HDMI out (ie not seeing all the info/controls along side/edges you see when looking through viewfinder).
Your best best is to ask in a Canon specific forum (like at canon themselves, or dpreview... or check YouTube videos?) regarding using your specific model camera as a webcam for the latest on recommendations, caveats, and more