Any link on your Insta website can be a 'Call me' link. When a visitor tap this, a message from the Phone app will popup asking for permission to make a call.
Here's how to set up the link:
1. Add a new Card to your Insta site or edit an existing Card
2. Tap the pencil symbol to edit one of the demo links.
3. Add some link text. In this example, that's 'Call me'. In the URL field type type 'tel:' followed by your phone number. For example: tel:0422334455
(Note there's no space between tel: and the phone number!)
4. Tap Done. Then Preview and Publish to update your Insta website.
A visitor on your Insta website can tap this link to call you:
iOS devices also allow a visitor to tap and hold on the link for more options: