This document provides guidance on successfully transitioning a website from HTTP to HTTPS. It outlines the process in three phases: pre-move preparation, such as obtaining and configuring an SSL certificate; moving to HTTPS, including updating internal links and redirects; and post-move tasks like monitoring and promoting the HTTPS site. Tips are provided throughout on important technical aspects like mixed content, crawl budget, and HTTP to HTTPS redirects. The overall message is that HTTPS migration is crucial for websites and there are many resources available to help with planning and execution.