Once you set a passcode on your iPhone, it secures all your apps and data. However, if you hand over your unlocked iPhone to nosy people, it's possible they will peek inside WhatsApp to see what you’re up to! Thankfully, WhatsApp offers a built-in option to lock the app.
This tutorial shows you how to enable a password or Face ID/Touch ID lock on WhatsApp for iPhone to protect your chats. The process to lock WhatsApp Business is the same.