It depends on your tier, and this is one of the real differences from some competitors, which include unlimited users at every level. QuickBooks allocates a number of billed seats per plan and charges for more, so the user count is part of the pricing decision rather than an afterthought. Your accountant is the exception worth knowing: accountant access does not consume one of your paid seats, so bringing us in costs you nothing in licences. Beyond that, plan for who genuinely needs to be in there — an owner, a bookkeeper, perhaps someone raising invoices — and set permissions rather than sharing one login, which is both a security problem and an audit trail problem when something is posted wrongly and nobody knows who did it.