In order to add modifiers to Online ordering menus, go to Admin panel -> Ordering & Menu -> Modifiers.

Then, follow these steps:
Click on Add new
Click on the arrow in order to access modifier settings

Here you can:
Rename the modifier

Choose between two types of modifiers:
Note

Options

In case you choose this type of modifier, you will also be able to select the multi-select option, as well as to add as many options as you want.
Link modifier to Categories

Click on the plus sign if you wish to link the modifier to some of these categories.

Link modifier to Products

Click on the arrow to choose the category first

Then, click on the plus sign if you wish to link modifier to some of these products.

Example of a successfully set up modifier

This is what you will see when making a new order
with Type -> Options enabled

with Type -> Note enabled

This is what your customers will see when making a new online order
with Type -> Options enabled

with Type -> Note enabled

For more articles on Online ordering, please visit our Help center.