1. Go to Settings > Device Options. Under Device Model if it says:
Fire 7 (7th Generation) or
Fire HD 8 (7th Generation) or
Fire HD 10 (7th Generation) or
Fire HD 8 (8th Generation) then it is compatible; If not, then it is not.
2. Alternatively, you may download one of our apps. If the app is not found on the App Store then its not compatible.
Reference the Amazon Fire Wikipedia Page for additional details regarding the Fire tablet naming convention.