Disable the ability to add some items to the cart for online sales, but still have them visible

1: Tagging Products:

Assign a specific tag to in-store only products, for example, in-store.
This can be done in the Shopify Admin under Products. Select a product, and in the Tags section, add the in-store tag.

2: Modifying Theme Code:

You will need to edit your theme’s Liquid files. This can be done under Online Store > Themes > Actions > Edit code.

3: Customize Product Template:

Locate and open the product template file (usually product.liquid or product-template.liquid) in the editor.
Insert conditional Liquid code to check for the in-store tag. For products with this tag, you would disable or hide the add-to-cart button.

Example code snippet:

{% if product.tags contains 'in-store' %}
  

This item is available in-store only.

  
  
{% else %}
  
{% endif %}