In most places it is paid parking. This is indicated along the road. You need to get a ticket from the ticket vending machine and pay on your return for the time you parked your car.
Sometimes there is a parking meter. Here you need to decide in advance how long you intend to park your car and pay for that time. If you park longer than expected, you need to add money to the meter to avoid getting a fine.
In areas where paid parking is not in force, you may find there is a Blue Zone. Within this zone, you are only permitted to park for short periods of time by clearly displaying a blue parking disc. You can buy them at large department stores. Before leaving your car, mark your time of arrival on the blue parking disc. You can recognise a blue zone by a nearby road sign. On this sign you can see the maximum parking time permitted, as well as any additional conditions such as specific hours during the day.