contacts icon is missing from my iPhone

The Contacts folder cannot be deleted. Check other folders and/or home screen pages and see if you can locate it. If not, you can go to Settings, General, Reset, Reset Home Screen Layout and that should bring it back.

Contacts and Mail can both be deleted from the iPhone under iOS 10.x. Do a spotlight search to see if they are on the phone, and if not, you will need to go to the App Store and download them again if you need the. See this support document on how to search and download the apps again if necessary. Remove built-in Apple apps from the Home screen on your iOS device with iOS 10 - Apple Support

Thank you for a very helpful suggestion. Unlike the ones above which were wrong as you can delete Contacts. I tried the others before yours and messed up all my icon organisation. Many thanks ChrisJ4203

My contacts app disappeared, and none of the calls in my call history, nor my text messages, are associated with contacts anymore. I went to download the Contacts app and was only given the option to open it, not download the app. I also tried resetting my home screen. Any advice?

In doing so, it will bring my home screen layout to factory defaults. Does that mean other icons/applications that I have added will dissapear?

my contacts disaperead a week ago, today the mail icon I reseted the home screen and they are still missing

Glad I could help.