Tap the WhatsApp icon on your iPhone’s home screen.
Scroll down and tap Blocked Contacts . Here you’ll see a list of everyone you’ve blocked on WhatsApp.
Inside the Account section, select Privacy .
Once unblocked, their name will disappear from the Blocked Contacts list. You can now message them or add them back to your contacts normally.
Swipe left on their name, then tap Unblock . Alternatively, tap Edit in the top-right corner, tap the red minus button next to their name, then tap Unblock .