Welcome to the Community, siewlan-tay.

QuickBooks Online allows you to easily reactivate an account from your Chart of Accounts. Simply follow the instructions below:

Here's how:

1. Go to Accounting menu.
2. Choose Chart of Accounts.
3. Select the account you want to reactivate and click the Make active link.

You might also want to check out visit this link to become more familiar with managing accounts in your chart of accounts.

I'll be right here if you need with anything about QuickBooks. Wishing you all the best of luck.