Does your printer support AirPrint? iPadOS/iOS devices support AirPrint over WiFi - this being a “driverless” printing protocol. There’s a bit of a clue as to how this connection works in the name... AirPrint being a print protocol that works over a network connection.
Unless your printer explicitly supports AirPrint over USB (which would be unusual), direct connection to the printer would require installation of a printer-driver, which can only be achieved by way of a printer App coded specifically for the attached printer model.
It’s worth looking at your printer manufacturers support site for specifications and details of any manufacturer-specific Print Apps for iOS; if an App exists, it will likely link back to the Apple App Store.
If your printer does not support AirPrint over USB - or you cannot find a corresponding App for your printer - then direct connection over USB won’t be possible.
AirPrint is commonly supported by modern printers that are designed for domestic or SOHO environments. AirPrint is frequently not supported by printers targeted at Business and Enterprise settings; some printers may simply be too old.
Where AirPrint is not supported, it is necessary to add an AirPrint Print Server on the network. The Print Server acts as the go-between for the iPad (or other Apple device) and the Printer. One example of a commercial appliance, that performs the AirPrint Print Server function, is the Lantronix xPrint Server. It is worth noting that the cost of a Print Server appliance may exceed that of a modern printer.
An alternative approach, where the Printer does not provide AirPrint support, is to connect the printer to either a PC or Mac - and use a print helper application. In this scenario, the computer becomes the Print Server. An example print helper application is available from Readdle:
https://readdle.com/printerpro
I hope this insight and information is helpful to you.