Hi @piotr,
There isn't a specific field for project numbers in QuickBooks Online (QBO). What you can do is use custom fields instead.
Follow these steps to enable this feature:
- Go to the Gear icon.
- Select Custom form styles.
- Tap the Edit link beside the Standard form style.
- Move to the Content tab.
- Click the top part of the sample invoice on the right side of the page.
- Scroll down, then press the Custom field link.
- Depending on your QBO version, you'll see up to three blank boxes with check marks on them. Remove these to all boxes but one if you only need to use a single custom field.
- Name it Project Number.
- Press Done.
At this point, each time you create an invoice you'll have a blank Project Number field on it.
Take a look at this article for more information about this process: Customize invoices, estimates, and sales receipts in QuickBooks Online.
To stay up to date with QBO features, I suggest you visit this page: The QuickBooks Blog. Each month, it shows a list of new features and improvements, along with their short descriptions.
Let me know in the comments below if you have other questions about custom fields in QBO. I'll be sure to handle them for you.