Understanding your iPhone and iPad model is important, since not all hardware features are available for all models. Also, older iPhones and iPads can't take advantage of the latest version of the operating system, which is called iOS.
There are a few ways to determine your exact iPhone or iPad model, but this method is the quickest and most accurate:
Step 1 - Find the Model Number
Go to Settings > General > About. Scroll down to find the model number and write it down
Step 2 - Do a Google Search
Search for your model number and look at the search results to find out which specific model of iPhone or iPad you own.
Apple also suggests that you can take the cover off of your device, and check the 5 digit model number.
Step 3 - Visit the Apple site to see specifics.
Apple has details specifications for all models of iPhones and iPads available on their website. You can find information about every iPhone or iPad every manufactured by Apple.
Identify your iPhone model - https://support.apple.com/en-us/HT201296
Identify your iPad model - https://support.apple.com/en-us/HT201471