WhatsApp use colored check mark symbols to indicate the status of your sent messages. A gray check mark indicates that your message has been sent successfully, two gray check marks indicates that your message has been successfully delivered to the recipient's phone, and two blue check marks means that the message has been opened (read receipts).
Many WhatsApp users are wary of the blue ticks, and find the read receipt feature to be an invasion of privacy. This article will explain how to prevent WhatsApp from sending or receiving read receipts.
How To Remove the Blue Check Marks in WhatsApp
Before beginning, please note that read receipts cannot be disabled for group chats.
Open WhatsApp and tap on the Menu button (represented by 3 vertical dots) and then select on Settings > Accounts > Privacy:
Clear the read receipts checkbox. Your settings will be implemented automatically: