General Settings Options

• Dynamic Error Message : Set your customized dynamic error message from here.

• Select Customer Group: Select the customer group to apply the limit from here.

• Consider Lifetime Quantity: Enable this setting for considering lifetime purchase quantity. “Not applied for Not Logged In customer group.

• Lifetime Quantity Error Message: Set your customized lifetime quantity error message from here.

Then move to the below path

Catalog > Products > Select Product > Edit Product

• Limit Quantity: Enter the quantity limit for the selected product.