Our sheet music is sized for 8.5 x 11 (letter-sized) paper. Regular printer paper can be used for printing the sheet music.
We can't guarantee that the sheet music will print correctly on other sizes of paper (such as A4). There is no way for us to test this since all sheet music has some least minor differences in terms of margins, number of elements at extreme edges of the page, etc. It is possible to reduce the size in your printer settings to get the music to fit on other paper sizes. However, this may reduce legibility of the music.