Скачать или смотреть How To Send WhatsApp Message without Saving Number on iPhone 

How to Send WhatsApp Messages Without Saving ContactsTo send a WhatsApp message without saving the number on an iPhone, use the wa.me/ link in Safari by typing wa.me/ followed by the full phone number (including country code) into the address bar and tapping "Go," or use the "Message to Yourself" trick by sending the unsaved number to yourself in WhatsApp, then tapping on the sent number to open a chat with it.
Method 1: Using the wa.me/ Link
This method uses WhatsApp's "Click to Chat" feature.
Open Safari on your iPhone.
Go to the address bar and type wa.me/.
Append the full phone number with the country code (e.g., wa.me/1234567890).
Tap "Go" to navigate to the link.
Tap the "Continue to Chat" button on the resulting page.
The chat will open in the WhatsApp app, allowing you to send the message.