Reading settings decide whether emails are grouped into conversations, whether opening an email marks it as read, and where Newton takes you after you archive or delete. On your phone you can also choose how many lines of preview each email shows in the list.
Steps
Desktop
Open Settings: press ⌘, on Mac, or Ctrl+, on Windows and Linux.
Go to the General tab.
Under Reading, switch these on or off:
Auto mark as read: marks an email as read when you open it.
Group emails into conversations: shows replies together as one conversation.
Go to the message list after acting: after you delete, archive, snooze or move the open conversation, go back to the list. Turn it off to jump straight to the next conversation.
iPhone, iPad & Android
Open the menu and tap the Settings gear at the bottom.
Tap General.
Under Reading, switch Auto mark as read, Group emails into conversations or Go to list after acting on or off.
To change the preview, go back to Settings, tap Appearance, and under List preview choose None, 1 line, 2 lines or 3 lines.
Good to know
All three are on by default, and the list preview shows 1 line.
With Group emails into conversations off, each email appears on its own and actions apply to single emails. Snooze still snoozes the whole conversation.
These settings sync between your devices. List preview is only on phones and tablets.
With Auto mark as read off, emails stay unread until you mark them as read yourself.