You can follow these steps to adding product categories to header navigation.
#A. Adding Product Categories to Main Navigation
First, click on Gear icon in Shop Page

Next, click Categories, you will see all product categories on right side

Next, hover on a category > Click 3 dots > Edit

Next, click on “ADD TO YOUR MAIN NAVIGATION”

#B. Adding Product Categories to Dropdown Folder
First, click on Gear icon on Shop Page

Find URL Slug. We will have: /shop

Next, open Shop Page and click on each category to find URL of Product Categories.
We will have
- /shop/bike
- /shop/design
- /shop/example

Next, in Main Navigation > Click Plus icon > Choose Dropdown

Name it “Shop”

Next, click ADD Page > Choose Link

Enter Product Category Name/URL (you have in previous step)


You will have

Result

Note: You won’t click “Shop” title. To make this clickable to Portfolio Page. You can use this code to Code Injection > Footer.
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.7.0/jquery.min.js"></script>
<script>
$(document).ready(function() {
$('div.header-nav-item>a[href="/shop2"]').click(function() {
var link = $(this).text(),
href = "/shop";
window.location.href=href;
});
});
</script>
