What’s the best order to remind users to complete their account information after registration

i'm designing a registration flow for an ecommerce app. Among the information needed, some information isn't needed immediately to complete registion. After filling in the minimum required fields, the user will be reminded later on to fill in the rest.

My question is, whats the best way to remind users to fill in the required information later. Would it be better to remind by

  • Email
  • Push notification
  • On app launch

One concern is if users ignore one reminder, should the same channel be used to remind them again. Or are some users more likely to ignore certain channels than others? What would be a good flow to remind users who miss or ignore the 1st reminder.