Hello there, @Aprilhu. Let me step in and share additional information about adding a line to your budget in QuickBooks Online (QBO).

Your budget in QBDT depends on the accounts in your Chart of Accounts. That said, you'll have to create an account to add a line item. To do that:

1. Go to Accountant and click Chart of Accounts.
2. Click the Account dropdown, and select New.
   
3. Choose an Account Type and click Continue.
4. Fill out the necessary fields and select Save & Close.
    

If you prefer adding a line item without creating a new account, it's currently unavailable in QBDT. We understand how this could be a need for business owners like you. Let me help you share your valuable insights with our software engineers so they can review your feedback and may consider including it in our future product upgrades. Here's how:

1. Go to Help and click Send Feedback Online.
2. Select Product Suggestion.
3. Enter your feature request, then Send Feedback.

Additionally, create forecasts in QBDT to predict future revenue and cash flow. To do that, refer to the Create a forecast section in this article: Create a budget or forecast in QuickBooks Desktop.

Keep me posted on any future concerns you have about budgets. The Community is only a few clicks away to assist you. Take care and have a good one!