You can view your emails in screen widgets if you are using iOS 14 or later.
To add a widget, do a long tap on the apps home screen on your device. Then edit the home screen. Tap on the "+" button in the top of the screen to choose a new widget.
Tap on AltaMail to choose a widget size and type then tap on the "Add Widget" button below.

Email action buttons are available for iOS 17 or later. You can tap to mark an email as spam or delete it. After the action button is tapped, then an undo button will appear for a few seconds to allow you to cancel the action.

You can edit several widget layout settings by doing a long tap on a widget and them choose "Edit Widget" from the menu. For example you can show or hide the email action buttons.

Lock Screen Privacy
If you are using iOS 15 or later then you can disable email content and action buttons in the lock screen.
Open the device Settings app. Then open the "Touch ID & Passcode" section. Scroll down and change the "Lock Screen Widgets" to display or hide private email data in the lock screen.