USB-C is a connector shape. It tells you nothing on its own about speed, display output or charging capability, which is why two identical-looking ports can behave completely differently.
Reading the symbols
A lightning bolt means Thunderbolt. A small D-shaped icon means DisplayPort alt mode. A battery icon means the port can charge the machine. If there is no marking, check the manual rather than assuming.
Cables are not interchangeable
A charging cable that came with a phone will often carry only USB 2.0 data, regardless of the connector. For a display or an external drive you need a cable rated for the speed you want.
What this means when buying
Count the ports that do what you need, not the ports in total. Three USB-C ports where only one supports display output is a one-monitor laptop.
