There are a couple places to manage User accounts, on the Users tab of a given QB app or via the "Admin Console." The latter has more options that depend on the your plan. Head over to My Apps, then Manage my account (right-sidebar) and click Users (left-sidebar). From there, you can click "Send password reset message" to send a reset link to the User.
I don't recall ever setting a password for a User (just triggering the email), but perhaps QB Support would be able to help with this?
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Brian Seymour
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