Hi Sandra!
To turn off conversation view from the Gmail app on iOS:
-click on the 3 bars to the top left
-scroll all the way down
-find the gear icon next to “settings” and click it
-click on the button with your account picture and email at the top of the menu that comes up
-under the “General” section, you’ll see “Conversation View”
-toggle the switch next to “Conversation View” to the off position
I hope that helps,
–Jake