In order to add a custom field to a product, you'll need to add the custom field to the category the product is using. That way, it will appear for all products using that specific category.

Let's add a custom field to the product below, a Macbook Air (M2).

Start by clicking on the category of the product.

Now, click on the Edit button.

Scroll down on the page until you see the Custom Fields section, and click on the Show button. This is where you can add your own custom fields that will appear for all products using this category.

These are the types of custom fields you can create:

You can also choose if the custom field should be a required field or not. To add options to a Dropdown List custom field, you just need to fill out the Dropdown List Content field using this format: ["Option 1", "Option 2", "Option 3", ...]

In this example, we've added one custom field; Touch Screen (Checkbox).

Once you've added the custom field, scroll down and click on the Save button. Then, go back to the product page and click on Edit Product.

After scrolling down to the bottom of the page, we can see that the custom field we added is now visible and can be filled out for the product!

Once we've filled out the custom field and saved, we can see that it now appears for the product!

In order to remove a custom field from a product, you just need to go back to the Custom Fields section of the Edit Category page and make the Field Title field empty for the custom field you'd like to delete, and click Save.