5E Dragon Human Form - Web the dragon magically polymorphs into a humanoid or beast that has a challenge rating no higher that its own, or back into its true form (the dragon's choice). Raw, only metallic dragons have the innate ability to turn into humanoid form. In a new form, the dragon retains its alignment, hit points, hit dice, ability to speak, proficiencies, legendary resistances, lair actions, and intelligence, wisdom and charisma scores. Most fairy tales and popular fantasy works (such as the hobbit) follow that pattern. Web yes, metallics are the only ones that innately gain the ability to change shape. Dragonborn (phb p 32) look very much like dragons standing in humanoid form, though they lack wings or a tail, have a breath weapon attack that they can use, and resistance to an element depending on what type of dragonborn they are. I've noticed however that in many stories dragons also can take human form, and that often seems like a mundane ability of them. Some planar inhabitants claimed they were the same goddess and others that they were as different as night and day, while still others said one was a reflection or avatar of the other. But a sufficiently powerful chromatic could learn to cast polymorph, assuming you're using the spellcasting variant rules.
Web yes, metallics are the only ones that innately gain the ability to change shape. I've noticed however that in many stories dragons also can take human form, and that often seems like a mundane ability of them. Most fairy tales and popular fantasy works (such as the hobbit) follow that pattern. Dragonborn (phb p 32) look very much like dragons standing in humanoid form, though they lack wings or a tail, have a breath weapon attack that they can use, and resistance to an element depending on what type of dragonborn they are. Raw, only metallic dragons have the innate ability to turn into humanoid form. Some planar inhabitants claimed they were the same goddess and others that they were as different as night and day, while still others said one was a reflection or avatar of the other. In a new form, the dragon retains its alignment, hit points, hit dice, ability to speak, proficiencies, legendary resistances, lair actions, and intelligence, wisdom and charisma scores. Web the dragon magically polymorphs into a humanoid or beast that has a challenge rating no higher that its own, or back into its true form (the dragon's choice). But a sufficiently powerful chromatic could learn to cast polymorph, assuming you're using the spellcasting variant rules.