Check out example codes for "use google fonts in css". It will help you in understanding the concepts better.

Code Example 1

<!-- To Add Montserrat font or any font as such -->
<!-- Go to https://fonts.google.com browse the font you like here, Montserrat-->
<!-- On the right click embbed and get the link similar to one given below-->
<link href="https://fonts.googleapis.com/css2?family=Montserrat&display=swap" rel="stylesheet">
<!-- add this ^ link inside your <head> tag i.e. before </head> -->
<!-- In css you can specify the font family as -->
font-family: "Montserrat", sans-serif;

Code Example 2

Check out the font names and change 'finger paint' to another font name to how different google font appears on webpage.
<!DOCTYPE html>
<html>
<head>
<link href='https://fonts.googleapis.com/css?family=Finger Paint' rel='stylesheet'>
<style>
body {
    font-family: 'Finger Paint';font-size: 22px;
}
</style>
</head>
<body>

<h1>Finger Paint</h1>
<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit.</p>
<p>123456790</p>
<p>ABCDEFGHIJKLMNOPQRSTUVWXYZ</p>
<p>abcdefghijklmnopqrstuvwxyz</p>

</body>
</html>

Code Example 3

<link rel="stylesheet" href="//fonts.googleapis.com/css?family=Open+Sans:300,400,600,700&lang=en" />

Code Example 4

body {
    font-family: '*Insert google font';font-size: 22px;
}

Code Example 5

@import url('https://fonts.googleapis.com/css?family=Open+Sans&display=swap');

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