In QuickBooks Online (QBO,) account numbers are manually entered. Let me show you how it's done. First, you need to enable the option and manually allocate for each account in your Chart of Accounts by following the steps below.
To enable, here's how:
Go to the Gear icon, then select Account and Settings.
Choose the Advanced tab.
In the Chart of Accounts section, click the Edit (pencil) icon.
Check Enable account numbers and Show account numbers.
Click Save, then Done.
Once finished, let's assigned the numbers to your accounts. Here's how:
In the right-hand menu select Accounting and then Chart of Accounts.
Click the drop-down next to View register on an account and click Edit.
Enter the account numbers in the Number column.
Click Save and close once done.
You’ll now see the number in the Number field in your Chart of Accounts. This will also appear in the Name area in front of the account's title.
If you view your Balance Sheet, you will now see your accounts in order by number instead of alphabetically. This can be a great way to better organize your accounts.