Font Services: Google Web Fonts Adobe Fonts fonts.com
Go to the website, Select the font you like, Copy the link of the font above your stylesheet link.
Ex:
<head>
<link rel="preconnect" href="<https://fonts.googleapis.com>" />
<link rel="preconnect" href="<https://fonts.gstatic.com>" crossorigin />
<link href="<https://fonts.googleapis.com/css2?family=Open+Sans:wght@400;700&family=Roboto:wght@700&display=swap>" rel="stylesheet" />
<!-- Insert the font link before your css file -->
<link rel="stylesheet" href="css/style.css" />
<link rel="stylesheet" href="css/normalize.css" />
</head>
Explaination of the link: https://fonts.googleapis.com/css2?family=Open+Sans:wght@400;700&family=Roboto:wght@700&display=swap
? means query, the following should be query parameters = means the value of the parameter + means space ; means and, you can add another size of the same font by adding ; & means another query parameter display=swap by default, display is set to swap