Everything here depends on whether the contents stay in when the bag goes down hard. An open-flap wallet is fine for carrying a set across an office and sheds pages in a car boot. A press stud, elastic or zip closes properly. Gusset depth is the second question, since a flat wallet will not take a bound report however wide it is. See document wallets, expanding folders and file storage.

Translucent A4 document wallets arranged on a bright office desk with reports, stationery and filing accessories for organised paperwork storage.
A4 Document Wallets

Shop A4 document wallets for reports, forms, school folders, office filing and everyday document storage.