WhatsApp's Click to Chat feature allows you to begin a chat with someone without having their phone number saved in your phone's address book. As long as you know this person’s phone number, you can create a link that will allow you to start a chat with them. By clicking the link, a chat with the person automatically opens. Click to Chat works on both your phone and WhatsApp Web.
To create your own link, use
https://wa.me/<number> followed by the person's full phone number in international format. Omit any zeroes, brackets or dashes when adding the phone number in international format. For a detailed explanation on international numbers, read this article. Please keep in mind that this phone number must have an active account on WhatsApp.
To create your own link with a pre-filled message that will automatically appear in the text field of a chat, use
whatsappphonenumber is a full phone number in international format and
URL-encodedtext is the URL-encoded pre-filled message.
To create a link with just a pre-filled message, use
After clicking on the link, you will be shown a list of contacts you can send your message to.