Hello there, @SSLD.
I'm here to help share some insights about customizing the fields on your transaction form.
Are you referring to the maximum number of characters you can enter in each field? If so, the character limit for the custom field is up to 30 characters. For more information about the most commonly used fields and its limitations in QuickBooks, you can refer to this article: QuickBooks Online file size and feature limits.
Also, you can check out this link if you need some information about adding custom fields: How to add custom fields to invoices.
Please let me know if you have other questions about the custom fields. I'm here to help however I can.
