Open WhatsApp
Go to Settings
Tap Privacy or Account if the policy prompt appears there
Read the updated policy notice
Tap Agree and Continue
If prompted, tap Accept
Update WhatsApp to the latest version if you do not see the prompt
Restart the app and try again
If the policy is not shown, wait for the in-app prompt to appear
If you do not want to accept, stop using the app and consider exporting your chats first