Mobile reverse navigation (back) and Auto forwarding pages

I have a couple of questions:

  1. When a user press back within a flow – do you show (when going back) screens that are “confirmation states” or steps that were needed to be field in order to continue the flow?
    Such as a confirmation code that was already sent and was confirmed?

If so:

  • Do you clear the form?
  • Keep the information field?
  • Show a message that this step was already taken?
  1. When going back – how do you treat states that are created in the server (such as pending / success confirmation)?
    Usually this states don’t have a back button, or a continue option – and auto direct you to the next screen. But i don’t want to confuse the user by removing it.

Is there a common practice when confirmation / validation screens can be auto transition and when it’s better to keep the user in the page and let him manually continue the flow?

I’m attaching an example for a courier app:

  • The courier has a list of goods
  • When pressing continue he needs to input a verification code that was sent to the client
  • Then the server is processing the payment (the client have field he’s credit card details already)or alternative checking the code.
  • And in the end – he signs the screen.

My question is – what should happen when the courier presses the back button on the last screen?
(we have a requirement to allow it)

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