Check out example codes for "html make phone number callable". It will help you in understanding the concepts better.

Code Example 1

<label for="phone">Enter your phone number:</label>
<input type="tel" 
  id="phone" name="phone" 
  pattern="[0-9]{3}-[0-9]{2}-[0-9]{3}">

Code Example 2

Area code with dashes, 1 and + sign

<a href="tel:+1-555-555-1212">555-555-1212</a>
Area code with no dashes, 1 and + sign

<a href="tel:+15555551212">555-555-1212</a>

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