Download the app , visit the Parkmobile website, or call the toll-free number on the green Parkmobile sign to register for a Parkmobile account; you will need your license plate number and a method of payment (credit card or PayPal). When you park in a space, use the Parkmobile smartphone app to access your account, or call the toll-free number on the sign. Key in your zone number located on the green sign (these zone numbers are different throughout the city). Opt-in to have Parkmobile send a text 15 minutes prior to the expiration of your parking transaction; You may either add time or return to your car on time.