Can modification be done once you have paid the fees online?
The payment of the fee that is requested during your online ESTA application request constitutes a form of final validation of your request. We would recommend you to review and verify the information that you have provided in the request form beforehand.
If you get to know that, you have committed one or two errors in the form, you can edit eta Canada form without any problem. But on the other hand, if you have already validated your payment, this modification will definitely be more complicated.
It is very important for you to understand, that only a few particular can be edited on your eta visa Canada request once you have made the payment online.
Here are the particulars that can be modified:
Your travel plan with etias visa application
The name of the airline that you are planning to fly with
The number of your flight
Your e-mail address