To read messages without letting the sender know you've read them, turn off read receipts.
You can star important messages by holding down on a message and tapping the star icon.
You can format your text by adding symbols before and after the words.
You can pin important chats to the top of your chat list. Just swipe right on the chat you want to pin, and tap the pin icon.
To reply to a specific message in a group chat, long-press the message you want to reply to, then tap the reply icon (an arrow pointing left) and type your response.
You can set custom notifications for specific chats.
Mute noisy group chats by going to the chat, tapping on the contact name/number, and selecting Mute Notifications.
Send the same message to multiple contacts without creating a group chat.
Use WhatsApp on your computer by going to web.whatsapp.com and scanning the QR code using WhatsApp on your phone.
Enable two-step verification for added security. Go to Settings > Account > Two-Step Verification > Enable and follow the prompts to set up a six-digit PIN.