Hello,
When you create a new account in QuickBooks Online, you pick a day to start tracking your business transactions. You enter the balance of your real-life bank account for that day so everything matches from the start. This starting point is the account's opening balance.
If someone forgot to enter an opening balance when they created the account, don't worry. You can go back and create a journal entry to record it and then get back to business as usual. I'll help point you in the right direction to see how.
Follow the steps in this article: What to do if you didn't enter an opening balance in QuickBooks Online. This article will guide you through the steps to enter an opening balance in order to get started on your reconciliation.
I hope this helps you get back on track. If you have any other questions, please reach out to our tech support team.
Cheers.
