You may have misunderstood the meaning of folio, which is actually a fraction of standard paper. Commonly used printing paper has two specifications: generous 889 x 1 194/ positive 787x 1092, and the standard finished product size after generous trimming is 850x 1 168, such as the one closest to A4.

So, first of all, you have to find out how much booklet you want to print is 850x 1 168 (that is, how many folio), so as to determine the size of the paper. Usually, the text is No.8. As for the font, there is no strict requirement, it depends on the content.