https://github.com/magesuite/magesuite-success-page-registration

This module adds a registration form on the checkout success page for guest users. The form is already populated with data provided by the user in checkout.

Installation

Admin settings

Stores -> Configuration -> MageSuite -> Success page -> Registration form

Open

Settings:

Frontend

Open

The registration form is the same form as displayed on the registration page. Fields that are already filled (f.e. name) are hidden by CSS.