If you want to set a maximum order limit on a product in your Shopify store, then It is possible with the  "MultiVariants - Bulk Order" app. This feature is available in the “Professional” package.

To get the feature, install the "MultiVariants - Bulk Order" app in your Shopify store and follow the procedure:

•  Navigate to app admin and click “Set Restrictions”.
•  Here you will see a section named “maximum quantity” in the Quantity restrictions section.
•  From there, you will see an option named “Total (combinations)”
•  Now, in the input field enter your maximum order quantity. 
•  Save the configuration and check it on the product page.