Hi there, Mohammed. You can create a purchase category using your Chart of Accounts in QuickBooks Online.

Here's how to do it:

1. Go to the Gear icon, then select Chart of Accounts.
2. Click New Account and enter your preferred account name.
3. Select an Account Type, such as Expenses.
4. Choose the appropriate Detail Type.
5. Indicate that it is a purchase category in the Description box.
6. Once done, hit Save.

This new account will serve as your purchase category for tracking expenses.

For more detailed information, check out this article: Add an account to your chart of accounts in QuickBooks Online.

Feel free to drop a comment below if you have more questions. We're always here to help.