Hello @Lorenzo127,
Is it that you want to stop Google's Gmail app, the one that has the icon showing an envelope with a red M, displaying your emails?
If yes, then open that app and tap on the 3 bars in the top left. Then scroll all the way to the botton and tap on "Settings".
You should then see your gmail account listed. Tap on this and then on "Inbox sound & vibrate".
Now tap on "Sync messages" and then tap on "None".
This will stop the Gmail app downloading email from your gmail account.
Or is it that you use another email app and want to stop that showing you Gmail emails?
I use the Android email app that has an icon showing an envelope with the "@" symbol on it.
If you want to stop that one showing gmail emails then open the app and tap on the 3 dots in the top right.
Then tap on "Settings".
If your gmail account is registered to this app then you should see it listed there.
Now tap on the 3 dots again and select "Remove account".
Then tap the check box for your gmail account and then tap on "Remove" at the bottom.
Steve.