I have an iPhone 6, so does my wife.
Normally, when at home, I keep my iPhone plugged into a usb port on my Win 7 computer, to keep it charged.
My wife had a photo on her I phone that I wanted to download onto my PC. I connected her phone to the USB port; computer did not recognize it.
So I decided to email the photo to myself. I tried to do that, it required I put an email address in, I put my gmail address in. Then I was able to email the photo to myself.
While I was trying this, it kept tryng to connect to iCloud (5 or 6 times at least), I kept telling it no.
Somewhere in this process, it loaded all my contacts (I think from Gmail) onto my wife's iPhone. How, and why it did that is a total mystery, but I've given up on trying to understand the iPhone, although I have over 40 years of computer tec hnical experience.
The question is, is there a way I can "mass delete" all the unwanted contacts off my wife's iPhone, or do I have to so it one at a time?
Can I like "delete all added yesterday" (or a specific date?).
It appears like you did more than "put in your email address" .. it sounds like you added a your email account to your wife's iPhone. Google support email, contact and calendar synching with iPhone.
You should go to Settings then Mail, Contacts, Calendars section
Select the GMAIL account you created
Toggle OFF the Contacts and Calendars and Notes .. and it should ask you if you want to delete the associated contacts from the phone.
Maybe you should also then DELETE the entire Gmail account from her phone