As stated in the WhatsApp Blog,
Starting today, WhatsApp will indicate which messages you receive have been forwarded to you. This extra context will help make one-on-one and group chats easier to follow. It also helps you determine if your friend or relative wrote the message they sent or if it originally came from someone else.
WhatsApp cares deeply about your safety. We encourage you to think before sharing messages that were forwarded. As a reminder, you can report spam or block a contact in one tap and can always reach out to WhatsApp directly for help.
Source – WhatsApp Blog