How do I add another field to my Invoices? (such as a "reference" area where I can note which job I am invoicing for, kind of like an internal PO #)

Hello @brainardcustom ,

You could accomplish this by using Projects within QBO.  Your sales invoices can be written to specific Projects, and each line on an expense, bill or credit card can be allocated to a Project.  This will enable you to run profitability reports by project, time cost by employee or supplier, and identify your unbilled time and expenses.

Each Project is linked to a customer and can be identified by Name or Number, whichever makes the most sense for your business.  It appears on documents as follows:  Customer Name:Project.

To turn on Projects:  Gear Icon-->Settings-->Company Settings-->Advanced-->Projects-->Toggle to On.

Hope this helps.  Good luck!