Hi,
In order to use an iPad for printing (without an extra app), the printer must support the AirPrint technology. AirPrint models are listed in About AirPrint - Apple Support. Which printer make and exact model do you have?
The iPad must be wirelessly connected to the same network (Wi-Fi router) as the AirPrint printer.
Use AirPrint to print from your iPhone, iPad, or iPod touch - Apple Support
In case of difficulties with AirPrint, and if the setup is OK, one could try the following procedure:
Power off the Wi-Fi router, the printer, the iPad, and all other devices/computers. Wait two to three minutes. Power on the router. Wait two to three minutes. Power on the printer. Wait a minute or two. Power on the iPad. Finally, power on all other devices/computers.