I mean that's not really a good answer because you need to ask why they are sending a spreadsheet back and forth. Like yeah using a shared spreadsheet saves them having to email back and forth, but it doesn't help formalize the process, include validations, or make the data available to other systems. And maybe it would turn out that none of that is actually helpful in this case, but if you don't make an effort to ask and understand what's going on then you won't know if there's some bigger problem that needs addressing.