When you have a home office or lots of stored files to move, consider purchasing boxes made especially for moving files and other home office items. File moving boxes are 16"x12.5"x10" and have an attached lid that lifts up easily. You don't even have to tape these boxes closed, unless you choose to, but most file boxes come with fold and lock tabs to make it easy to secure your home office paperwork. You simply place your file folders in the box, shut the lid, and lock!
You must assemble these boxes once they arrive in the mail as they are shipped flat or purchased flat from a store. You can usually buy these boxes in bulk, typically coming 12 to a pack and generally costing a bit less than $40.