The type of oil for a 2010 Ford Explorer depends on the engine it has. There were several engine options available that year. To know for sure, you need to check your owner's manual. It will specify the exact type and weight of oil recommended by Ford.
However, generally speaking, 2010 Ford Explorers commonly used either 5W-20 or 5W-30 motor oil. Again, check your owner's manual to be absolutely certain. Using the incorrect oil can damage your engine.