HTC One M8 for Windows - Manual (Page 121)

You can also just tap on the far left of an email to select the email
first. Check boxes will then appear and you can select more email
messages.
Deleting, moving, flagging, or marking one email
1. Press and hold a conversation or a single message.
2. On the options menu, choose what you want to do with the whole
conversation or the single message.
Switching to another mail folder
1. Tap > folders.
2. Tap show all folders to see all the available mail folders.
3. Tap the mail folder whose email messages you want to view.
Changing email account settings
1. On the Start screen, tap the email account that you want.
2. Tap > settings.
3. Tap sync settings to choose how often to download items or
change the items that you want to sync.
4. Choose if you want a signature to appear in your sent email.
Email 121