How to use the email flags option in IOS Mail client

Step 1: Open Mail application on your iPhone device.
Step 2: Now open any email message which can be located at mailbox folder and not just from the inbox folder.
Step 3: Locate and click on the ‘Flag’ button from the bottom of screen.
Step 4: Now an orange flag icon will be appeared on the flagged message.
Step 5: The flag icon will retain on the email message until you manual delete or unflag that email.