Hello, How can I add the mileage calculations to an invoice? In the Desktop method I saw the option for additional expenses, but do not see it here on the online version

Hello dear, SDM2.

Adding the mileage calculation to an invoice in QuickBooks Online is unavailable. 
 

I like your idea where we can add the mileage calculation in the invoices. This is a great suggestion that I can send to our software engineers. I'm  making sure to forward the information you've shared here.

Our engineers will evaluate your suggestion. This way, adding this feature might be included in the next product updates.
 

We always want to hear from you. Please post again if you have additional questions when adding transactions within QuickBooks. Take care!