I always find the conversation views annoying, I prefer reading emails in the order they are received. So here is how to turn off conversation / threaded view in some of the email clients:

OUTLOOK 2016
Under the “View” tab, there is a checkbox with “show as conversations”, when checked you can also customize how the conversations are shown

OUTLOOK WEB MAIL

Don’t go to settings, just click on the drop down menu “Filter” on the top right corner of the mailbox, at the bottom you’ll find “show as”, just choose “messages” instead of “conversations

 

iPhone

Stop looking for it in the actual email app, go to the general settings, scroll down to “Mail, Contacts and Calendars”, then then look for “Organize by thread”. Turn that off and you’re good to go.

Gmail

Go to Options (the cogwheel top right) choose “settings”, stay on the General tab, and then look for “conversation view”