Letter fold out is the most common type of brochure fold when printing a double sided brochure. 3 panels of equal width are folded onto one another to create a standard brochure that you often see in racks at stores.
A “Z” fold brochure is created when 3 panels of equal width are folded in opposite directions to create a “Z” like appearance. This type of fold is also referred to as an accordion fold. This type of brochure can be found in racks in stores and other places but you don’t often see a “Z” fold brochure mailed unless it is inserted into an envelope. If you are looking to mail a brochure by itself then your best choice is the letter fold out brochure.