META has set some rules for when links are (or not) clickable in WhatsApp templates. These are as follows:
A link is clickable in a WhatsApp template if...
The sender's WhatsApp number is saved as a contact in the recipient's phone
Messages have previously been exchanged between the customer and the company on WhatsApp
The customer initiated the WhatsApp conversation
The contact uses WhatsApp with an Android device
The WhatsApp business account is an official business account
A link is not clickable in a WhatsApp template if....
The first message was business initiated
There has never been any contact between the customer and the company on WhatsApp before
The number of the business is not saved in the customer's contacts
The WhatsApp business account is not an official business account