If you are very worried about being stolen and reading some messages, you can actually hide the notification preview, so that only one message will be displayed, and the person and content summoned will not be displayed. If you want to open it, you must unlock the phone, which ensures everyone's privacy.
How to hide iPhone notification preview?
Go to settings > notifications > show preview:
Change it to When Unlocked or Never to display the preview. Please note that this is not a closure notice. You will still receive the notification, but the message content will not be displayed on the notification.
Turn off notification preview for a specific application.
If you often use notifications to read emails, so you need to preview the content, but you don't want strangers to see your messages or lines directly from the notifications, then you can turn off the preview of specific applications. Go to Notifications, scroll down to find the app, and then click Show Preview at the bottom:
Just change to unlock or never unlock.
Effect of closing notification preview
The picture on the left is the picture before closing. After closing, it will be like the picture on the right, and strangers can't see your news from the locked picture!