How to add modifiers during checkout process?

[Jasmin76]

to add items to the menu but have categories to modify how they want their product fixed.

ex: Brownies- milk chocolate versus dark chocolate. Nuts or without. Caramel drizzle on top. With or without liquor and if it has liquor in it which kind would you like added so they can get exactly what they want on their order.

[mattd]

You can create modifiers for your Square Online Store for individual items by going Online Store Dashboard Items > Item Library and clicking on the item you want to add the modifier for. Under the item there is a modifier section, there click 'manage modifiers' to apply and create modifiers for the item. You can customize these to your need, here is more on item modifiers.