Hello there, Javier. You can go to the Gear icon to add a custom field to a bill.

Here's how:

1. Navigate to the Gear icon.
2. Go to All Lists and select Custom fields.
3. Click Add field to create a custom field.
4. Enter a descriptive name to identify the field.
5. Choose the Data type for your field, such as Text, Number, Date, or Dropdown.
6. Under Select forms, check the box for Bill.
7. Once done, hit Save.

Please note that the ability to add custom fields and the number of fields you can use per transaction depend on your QuickBooks Online subscription plan. For more details on limits and usage, check out this article: Add custom fields to sales forms and purchase orders in QuickBooks Online.

You can revisit this thread if you have follow-up questions.

Hi, Javier.

I’m following up to see if the solution we provided worked for you.

Did it resolve the issue, or are you still experiencing difficulties?

We're happy to assist further if you need any more help.