You can reactivate your expense account by going to the Chart of Accounts (COA), sleiben.
Here's how:
- Go to the Gear icon
- Select Chart of Accounts.
- Click the gear icon and check Include inactive.

- Find the expense account, then click Make active in the Action column.
You can check this article for more details: Make an account inactive on your chart of accounts in QuickBooks Online.
For future reference, feel free to visit this material if you want to learn how to assign numbers to organize your COA: Use account numbers in your chart of accounts in QuickBooks Online.
Don't hesitate to drop a comment below if you need further assistance with your accounts. We're always here to help.