Scroll down this page to see "Why don’t I have the Get Windows 10 app?"
https://www.microsoft.com/en-us/windows/windows-10-faq
There are some potential huge gotchas with the "free" Windows 10 upgrade. I highly recommend doing a little Googling before upgrading.
e.g., 'Free' Windows 10 Has 3 Massive Unanswered Questions - Forbes
Here's a critique of Gordon Kelly's Forbes blog posts regarding Windows 10.
Just sayin . . . read with a discerning eye.
Should I upgrade to Windows 10? Forbes says no for boneheaded reasons | BGR