An iReal Pro chart is a single page, holding at most twelve lines (systems) and 208 spaces, and the player plays that page. There is no second page to turn, so there is no way to make a two-page chart. Longer charts are on our list.
 
A chart written to be played is not the same as a chart written to be read. A player chart needs every measure the band plays, while a reader chart can lean on repeat signs and jumps to say the same thing in less room. Writing the song as a player chart is usually what makes it fit.
 
When a song still will not fit, make the bars narrower rather than look for a thirteenth line. For a short song, you might even fit a second song on the same page. There is a discussion of multiple-page charts in the Forums.
 
For the full guide, see Chart layout and spacing on the iReal Pro website.