Can I add modifiers or add-ons to items?

Yes.

1. In Catalog, add or edit a product and open Modifier groups.
2. Click Add modifier group, add options with any extra price, and tick Required or Multi-select.
3. Save.

On POS and the Android app, the choices appear when the item is tapped, then Add to cart. Bundles are set in the Bundle section of the product form; a bundle cannot have its own modifier groups.