I'm using Edge and also checked chrome and it's showing for me. I'm at a loss as to why it's not showing for you.
Here is the link to the product registration form, the submit button is at the bottom of the page.
I just purchased a MFP C235 printer, but when I tried to register the product after filling in all the personal information and info about the printer, I could not find the submit button to complete the process. I tried so many times, all the same. Any help ??