How to define a variable?

Question

PHP

Hello,
In the database there is a text template in which there are variables, how to substitute a value instead of variables?Ваш номер: $tel

<?php
$tel = "790000000";
$a = bd($sql)['text'];
echo $a;
?>

Answer 1

https://www.php.net/manual/en/function.sprintf.php

$tel = "790000000";
echo sprintf("Номер телефона: %s", $tel);