The wording here is the wording in the app, on purpose — a setting that is called one thing on a website and another on a phone is a setting nobody trusts.
Account → Driving for. Each one is a row you tap on or off, and your map menu shows the same list back to you so there is never a question about what you are signed up to carry right now.
One rule: the last one cannot be switched off. A driver carrying nothing is not a state worth having — if you want to stop, go off duty.
Your choice is recorded on your driver profile and shown wherever your work is described. Using it to filter which offers ring your phone is the next step in this system, not something it does yet — so if you turn something off today, say so to a shop that asks you directly.
* Free to join, and a delivery job never costs you anything — the rate you set is yours. The one exception is a PickMe ride, where a flat 99¢ comes off your balance per trip; that is the whole of what Cyca takes, and it does not grow with the fare.