Follow the steps below to install jQuery on your store
In your Store Admin navigate to Sales Channels > Online Store > Themes On the Themes page.
Click the three dots on the Current theme and select ‘Edit code’ as shown below.
Insert the following code into your theme.liquid immediately above content_for_header as shown below and click “Save”.
<script src=”https://code.jquery.com/jquery-3.6.4.min.js” integrity=”sha256-oP6HI9z1XaZNBrJURtCoUT5SUnxFr8s3BzRl+cbzUq8=” crossorigin=”anonymous”></script>