Printing from iPad

iOS/iPadOS doesn’t natively support direct connection to a USB Printer. Instead, these devices use a network connection to supported printers typically over WiFi - or if explicitly supported by the printer, a wired ethernet connection.

See:

• Use AirPrint to print from your iPhone, iPad, or iPod touch - Apple Support
• Connect an AirPrint printer to a Wi-Fi network - Apple Support

Apple AirPrint is a driverless connection protocol. A high proportion of modern printers intended for Home, SoHo and Business environments now support AirPrint:

About AirPrint - Apple Support

If your Printer does not support AirPrint, WiFi Direct is simple wireless alternative - but will require use of an appropriate App supplied by the Printer Manufacturer (e.g., many HP Printers use the HP Smart App).

A further alternative is to add AirPrint support to your existing USB Printer using a Print Server (e.g., Lantronix xPrintServer - or a Raspberry Pi running CUPS). Both are viable, however, you may find that purchase of a cheap AirPrint-capable printer may be more cost effective.

Not to my knowledge no. There is no documented support for wired printers on iPad.

Your Printer manufacturer may offer an App that can connect directly to the Printer over a Wi-Fi connection (without requiring an existing Wi-Fi network) or over bluetooth.

Check the printer's user guide for details.