About kept messages
When you use disappearing messages in your WhatsApp chats, you can choose to keep messages in the chat to prevent them from disappearing, as long as the duration time has not passed. Once the message has been kept, it will be visible to everyone in the conversation and not disappear when its duration expires. All messages that are kept will appear in the Kept messages folder in your WhatsApp settings.
Your privacy is our priority
If someone keeps a message you've sent, you'll get a notification. As the sender of a message, you have the ultimate control over who can keep your message. If you decide to unkeep your message, no one else in the chat can keep it again.
Keep a message
Anyone in the chat can keep a message. Group admins can restrict this based on the group admin settings, and limit it to only admins if they choose.
To keep a message, click or long press on the message you want to keep and tap or click Keep.
To view your kept messages, tap or click on the chat info > Kept messages.
Unkeep a message
You'll have approximately 30 days from the time a message is kept to unkeep it.