No, it is not necessary to run water separately when using a washing machine. Washing machines are designed to automatically fill with water during the washing cycle. They have built-in water inlet valves that are connected to your home's water supply. When you start a wash cycle, the washing machine will open the water inlet valve and fill the tub with the required amount of water based on the selected settings.
However, it's worth noting that some modern washing machines come with features like "water-saving" or "eco" modes, which allow you to reduce the amount of water used for a cycle. These modes may require you to manually adjust the water level or use sensors to determine the appropriate water level based on the load size. In such cases, it's important to follow the instructions provided by the manufacturer.
In summary, you don't need to manually run water into the washing machine before starting a cycle. The machine will automatically fill with water as needed based on its design and the selected settings.