How do I install a Twain driver for a Canon scanner?
To install the Twain driver verify the scanner in the Device Manager. For this Start Settings Control Panel and double-click the System. If it appears here the scanner is connected. Now select Hardware Device Manager.
How do I install driver of Canon LBP 2900B printer for a MacBook Pro running on macOS Mojave?
generally just plug in the USB cable and it should automatically download the relevant driver from its database online. you should see it installed in the printers&scanners in system preferences.
How do I use a scanner on Windows 10 which is not compatible?
I assume you are talking about an old scanner for which no driver is offered for Windows 1. I actually had that problem myself with an old Canon scanner which I had initially installed on a Windows XP machine. Canon had (annoyingly) failed to provide a driver for Windows 8 (7 OK). I made it work on my Windows 8 machine by running Windows XP in a virtual machine. A USB device can still be accessed by the virtual machine. (Alas my trusty old Canon scanner has since failed. I replaced it for $7 with an Epson which is actually much better and supported.)