Former house manager here.
95% of house reports are trivial: house count, box office and coat check take, and a remark to the effect that nothing unusual happened. (Maybe the show went up two minutes late. Not a big deal.) With this in mind, make it as easy as possible for house managers to file that information: don't give them a six-page form when they're only going to fill in 3 of the boxes and leave the rest blank.
I actually recommend producing a cover sheet and leaving it at that. (A box for the house count, a box for the financial take, the usual information about the show/venue/event, and whatever other pertinent information should always be recorded. Nothing else.) If the house manager needs to make notes, rather than trying to anticipate the sorts of information they need to record, have them write it out freehand on separate sheets of paper and staple it to the cover. (And if nothing happens, they can just submit the cover sheet without any attachments.)
For complete accuracy, you might want the cover to include a sheet count. ("Attached: ____ Pages", with the house manager filling in the blank. Most days it'll be zero.)