“Flash” is an adobe product that allows websites to make very feature-rich pages. Flash is available on some platforms and not on others.
Tablets/Phones
Apple iOS products (iPhone, iPad) do not support Adobe Flash, so you might find that some websites don’t display properly. There isn’t much you can do about this on an iOS device. However, many websites have moved from Flash to HTML5 which gives websites most of the functionality needed, and they work with Apple tablets.
Other Tablets (Android tablets/phones, Windows Surface etc.) do work with Flash websites. If you need to use a tablet/phone and there is a website that you specifically need that uses Flash, then these products may be more advantageous. Make sure you update your Flash regularly on these products.
Computers
Apple OSX and Microsoft Windows desktop computers (and laptops) run Flash.
Make sure you upgrade your Flash to the latest version (www.adobe.com), as there are always security updates and product improvements.