If you keep your read receipts ‘on’ in WhatsApp, a blue tick appears next to the message when the recipient has read it.
iMessage users can toggle off read receipts for select chats
Read receipt hides text delivery information from the sender
This is useful for users who want to keep things more private
How to Turn Off Read Receipts in Facebook Messenger, Apple iMessage, WhatsApp
WhatsApp users can toggle off read receipts from Settings
WhatsApp, Facebook Messenger, and Apple’s iMessage — all three apps have the read receipt function that notifies the sender when the receiver has read their message. Read receipts are an important part of communication through messaging apps. It allows users to understand whether their message has been seen by the recipient or not. WhatsApp, Facebook Messenger, and iMessage support the read receipt function by has different ways of notifying the sender that their message has been read. But if you like to keep things more private and not allow the sender the freedom to know when you have read their message, you can turn these read receipts off at any time. For instance, if you keep your read receipts on WhatsApp a blue tick appears next to the message when the recipient has read it.