Paper is too small for frame

The largest paper size my printer will take is A4 however it is too small for my box frame which is 23cm x 23cm. I need the printer for wording. One idea is to cut out a border for the two short sides in coloured paper. I think with white paper with white paper you'd notice where the paper ends. Worried things wont look or cut straight enough.I would like to stick to this frame size as it's the most affordable from ikea. Any suggestions would be great. Needs these to look professional enough to sell