How to add link to a phone number in message bubble and buttons

There are times when the user wants to give you a call directly from the bot. Here is how you can add a hyperlinked phone number in the bot, click on which will open the caller app : 

In the message bubble

1. Select the text you want to hyperlink.
2. Add this link to it - tel:phone_number where phone_number is the number to be added. Replace phone_number with the number that you want to have in the actual bot.

Here is a gif that shows this -

In the buttons

1. Add a button and write the text you want to have on it
2. Now click on + sign next to the button and then select the external url icon
3. Add this link to it - tel:phone_number where phone_number is the number to be added. Replace phone_number with the number that you want to have in the actual bot.

You are done. Click on Save button to save the changes.

Here is a gif that shows this - 

And this is how it would look like when a user clicks on the phone number in the bot :