If I upgrade to Windows 10 ,will I loose favorites stored on IE 11 on my 8.1 OS?

What is the definition of "mainstream support" and "extended support"?
Please pardon my ignorance as I am technology challenged.

My present OS is Windows 8.1.
(1) All I use my laptop for is email, web browsing and on-line purchases such as amazon.com, etc. I am accustomed to using 8.1 for the aforementioned and am happy with...