How do I start entering bank information when the business owner has been using her personal bank account for business transactions?

Good morning contact-karenfah,

Thanks for reaching out to us here and Welcome to the QuickBooks Community! QuickBooks Online is a great tool that helps keep your books balanced. I would be happy to provide some information.

Ignoring transaction will have a negative impact on your books. I encourage you to take a look at this article for assistance on how to record business expenses you made with personal funds. If you require additional assistance, I recommend reaching out to our support team outside of the Community. They'll be able to verify your account details in a secure setting, as well as view your screen to better assist you. You can reach them by following one of these methods:

Schedule a Callback or start a Chat: click (?)Help in the upper right > type and enter "Contact support" into the QB Assistant > click Contact Us > explain your situation > click Let's Talk > choose Get a callback or Start a Chat.
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If you have any other questions, feel free to reach out here.