Like people have a ton of shrimp(for example) on like a sheet of paper. How would I do that? Can I do it with willows?

Those are notes, and you can note almost anything, willows included. When your in your bank, before you withdraw the item(s) you want noted, there's a button on the lower right side of the bank page that says Note, click that and then you will get the item(s) withdrawn in notes.