Hi and Welcome. My Name is ***** ***** I look forward to assisting you today with your question.
What version of Windows are you using on your PC ? 7,8, or 10 ?
You should initiate the scanning process directly from computer. There are many ways to Scan a document. First method is, click on Start menu and look for an app named Scan. Open it and use it to Scan.
If you don't see Scan app, then type Scan at the windows search box and this will show Scan app. Open it and use it to scan. If you don't have it, then you can get it from here --> https://www.microsoft.com/en-in/store/p/windows-scan/9wzdncrfj3pv
Another method is (if you have installed the disc came with it), search Canon Scan or IJ Scan and if it finds anything, open it and use it to scan.
If you don't have that app, then go to this website and download the "MX490 series Full Driver & Software Package (Windows)" --> https://www.usa.canon.com/internet/portal/us/home/support/details/printers/inkjet-multifunction/mx-series-inkjet/mx492
(Go to above website, click DRIVERS AND DOWNLOADS. Then download the Full drive and software package, open it and follow the onscreen instructions to install it).
After installing it, you will see the Canon Scan or IJ Scan app which will allow you to scan.
If you have any difficulty on following the steps above, please let me know and I will continue to help you