Hello samanthaconnell0, welcome, and thanks for posting on the Quickbooks Community page, if you have more than one business then you will need to have more than one Quickbooks account as it is one business to one Quickbooks account. If you have created two QuickBooks accounts under the same email address and log in. When you log into the app it should ask you which company/business you want to go into and then you just select that company and it will open that account up for you to use.
