delete email on iphone but not pc

My wife and I both have iphone 7 and use the included email program. We both have emails with Century Link within the email program. When I delete an email from my phone it remains in outlook on my computer (Office 365; windows 10). This is what I want. When my wife deletes an email from her phone it is also deleted from outlook in her computer (Office 365; windows 11). She does not want this. I have spent hours (literally) with the microsoft community trying to resolve this problem. They were most patient with me but finally decided that the problem was outside their purview; that I needed to contact apple. It would appear the issue is that my wife's account on her iphone is imap and that this is the problem. I don' understand this because the Century Link site says it should be a POP one...and presumably mine is since I don't have the problem. Both accounts were added on the same day when we purchased our phones.