The Ricoh SP 203sf is not supported by Apple's built-in AirPrint technology, though it does support 390 other Ricoh models. If Ricoh does not provide drivers for this device on your version of macOS, then you are done and time to consider another printer choice with AirPrint support — so you don't get in vendor driver jail again.
The SP 203SF model is so old, it does not appear on Ricoh's discontinued product listings. Thus, I suspect any hope of obtaining a current device driver for this printer is long gone. I would discourage you from obtaining any driver from sites whose domain name does not end in ricoh.com.