While there are many different types of Philodendron, the most commonly seen and used indoors is the Philodendron Cordatum, sometimes called Sweetheart Vine or Heart Leaf Philodendron.
This Philodendron has heart-shaped, green leaves that are typically about 2-3 inches across although they will grow much larger outdoors.
A trailing or a climbing plant, this Philodendron is the one most often used as an interior houseplant.