How to find out which model Phone you have
Before purchasing a phone case it's a good idea to double check which exact model you are purchasing for to ensure you select the right size case to fit your phone and avoid the disappointing scenario of finding it doesn't fit when it arrives. For example the case for a Samsung S20 is not the same size as for a S20 FE, and the iPhone SE first generation (2016) is not the same size as the second generation SE (2020).
Find the model on a Samsung phone
Go to Settings>About phone (sometimes called 'About device'). Tap 'About phone' and it should open a screen showing you the phone model in addition to other information. On some phones 'About phone' is found in Settings>System>About phone.
These steps can also be found on the official Samsung mobile device support page (the section called 'Through the Settings').
Alternatively find your model by comparing model dimensions on the official Samsung site.
Find the model on an iPhone
Go to Settings>General>About
The About section will list the model number. For an iPhone earlier than an i7 the model number is given on the back of the phone. You can then identify model you have, for example a 12 or a 12 Pro, from the official Apple iphone identification page.
Alternatively find your model by comparing model dimensions on the official Apple site.