The first thing you need to do before transferring a domain is go through your domain provider’ transfer policy.
You can find the necessary information in your domain provider’s help center.
Here are the transfer policies of some of the most known domain providers:
Check if the email associated with your account is valid. During the transferring process you'll
have to respond to all the emails you’re going to reveive.
-unlock the domain that you will transfer. This can be done through the « settings » section of the domain provider’s website. your domain providers might ask you to approve your choice by clicking on a link in a confirmation email.