Framing guide
All prints sold are made to be displayed with a matted frame. That is a kind of frame with a piece of board (usualy white) infront of the image that acts like a border around the photograph.
In order to get a frame that suits the print, make sure you get the right size of the frame and mat.
When looking for frames for A4 prints, look for something like A3 Frame with A4 Mount. Use this guidance to find a suiting frame size.
I would personally recommend Amazon or your local arts shop. If you have any further questions, ask me anything, im always happy to help!