When a circuit has been designed and printed on a PCB, what is left is assembly and testing. All the capacitors, integrated circuits, resistors, inductors, diodes, sockets, connectors, cables and buses must be installed. The board must then be connected to a power source to test if everything functions as intended. If you are in the electronics manufacturing industry, you will need a supplier of printed circuit boards as well as a circuit board assembly provider.
There are many PCB assembly companies but they are not all equal. When comparing service providers, there are many things you need to look at. For starters, you should compare the years of experience different firms have. Be sure to also compare the rates they charge. Since you will also need testing services, be sure to confirm that they do testing to ensure every assembled board is in good working condition.