PayPal Shopping increases conversion. You better believe it.
Before using the Web SDK make sure you have required it by adding this tag on every page that you intend to use the SDK. You do this by adding this code snippet in your element.
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<script src="https://www.paypal.com/sdk/js?client-id=SB_CLIENT_ID&analytics=custom"></script>
</head>