I have run across some confusion recently about the Google Change of Address Tool, which I wrote about recently. While the Change of Address tool is still broken in my opinion, it’s important to note that the tool is only really meant for moving from one domain name to another.
If you are changing your website from HTTP to HTTPs, then you really do not need to use the Google Change of Address tool. In fact, technically speaking, you’re not moving (to another domain). You’re just internally changing the site, you’re making the site more secure than it was before. It’s still the same website, the same domain name. The same goes for moving from http://billhartzer.com to http://www.billhartzer.com, where www is a subdomain. Again, you’re not moving to another domain name. So, most likely if you try to use the Change of Address tool, you’re not going to see that subdomain in your list of sites that you’re “moving to”.
There are a few things that you need to do when you change to HTTPs from HTTP, and I have a checklist of those things here on my website:
What I do recommend is that you verify each version of the site in Google Search Console, and especially the HTTPs version of the site. And, you’ll also need to consider uploading a new Google disavow file if you previously uploaded one for the HTTP version of your website.
Note that this issue has been around for a while, and Barry over at SE Roundtable posted about it back in 2014.