shipping/handling on invoice

you can not add the field, you have to use an item

service item called shipping which posts to an income account, I use one called pre-paid shipping income

@JMAColorado

In QBO, they do have an option to add a Shipping field on Invoice form.

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You will need to enable this from the gear sales settings.
(Gear on the top corner > Your Company > Account and Settings > Sales > Sales form content > Shipping > On > Save).

You can select Shipping account from the gear advanced settings.
(Gear on the top corner > Your Company > Account and Settings > Advanced > Chart of accounts > Shipping account > Select account > Save).