@CherylM,
Does your printer have a WPS button or menu option? This would allow you to set up your printer on the network without the password and by simply pressing a button on your router and printer within 1 minute of each other.
Using the WPS Function on Your Router
The screen may also be only showing 7 Digits at a time, if there is a way to view the characters as you are inputting them you may be able to see if the input box is scrolling as you type.
A lot of printers will also now provide their own phone applications, depending on your brand and model, you may actually be able to configure the network settings through this. I highly recommend looking for a WPS option as this will be the most stress free option for you.