In Short.. NO
In long, yes if you don’t mind logging onto a computer:
Info from 1tap:
Unfortunately, it’s not currently possible to use the email-in feature for income. However, we’re actively working on it and we’ll be happy to update you as soon as it’s released.
As an alternative, I can suggest using the online solution for the app – called 1tap online. It allows you to directly import files from your computer to your 1tap account. You can check it out here: https://my.1tap.io/.
It is freely accessible with your 1tap account and the data between the apps is automatically synced.
Once logged in, please follow the instructions here to submit your invoice: https://support.1tap.io/hc/en-us/articles/115004428749