What is the difference between an online and a mobile phone ticket?

Online ticket
An online ticket is a ticket booked online on int.bahn.de that is provided digitally in PDF format after purchase.
During a ticket inspection on the train, you can show the online ticket either on your smartphone, tablet or printed out. You can also use most offers as a mobile phone ticket in the DB Navigator app after booking online.

After booking an online ticket, you will also receive an e-mail with a PDF attachment. This gives you a receipt for each booking that you can then submit for expense claims or tax deductions, for example.
Mobile phone ticket
The mobile phone ticket is a digital ticket that you use in the DB Navigator app on your smartphone or tablet.
You can book it directly in the app or buy it on int.bahn.de. When purchasing via int.bahn.de, the ticket will also be displayed directly in the app, provided you are logged in there with the same customer account.