Your lineage stems from a dragon progenitor. Choose the kind of dragon from the Draconic Ancestors table. Your choice affects your Breath Weapon and Damage Resistance traits as well as your appearance.

When you take the Attack action on your turn, you can replace one of your attacks with an exhalation of magical energy in either a 15-foot Cone or a 30-foot Line that is 5 feet wide (choose the shape each time). Each creature in that area must make a Dexterity saving throw (DC 8 plus your Constitution modifier and Proficiency Bonus). On a failed save, a creature takes 1d10 damage of the type determined by your Draconic Essence trait. On a successful save, a creature takes half as much damage. This damage increases by 1d10 when you reach character levels 5 (2d10), 11 (3d10), and 17 (4d10).

You can use this Breath Weapon a number of times equal to your Proficiency Bonus, and you regain all expended uses when you finish a Long Rest.

You have Resistance to the damage type determined by your Draconic Essence.

You have Darkvision with a range of 120 feet.

When you reach character level 5, you can transform as a Bonus Action using one of the options below (choose the option each time you transform). Once you transform, you can’t do so again until you finish a Long Rest. 
Here are the transformation options:
True Dragon:
You unleash your full draconic essence to reach your true draconic form. You gain the following benefits:

• Your size increases from Medium to Large.
• You gain a Fly Speed equal to your Speed.
• You gain additional uses of your Breath Weapon equal to half of your proficiency bonus rounded down. These additional uses can go over the total uses of your Breath Weapon, but they are lost the moment your transformation ends. For example, if you transform into a True Dragon at level 5 while not having spent any uses of your Breath Weapon, you now have 4 uses of your breath weapon. If you end your transformation without spending any of these uses, you would have 3 uses, having lost the extra use given by acquiring this form.

The transformation lasts for 1 minute or until you end it (no action required).

False Person:

You assume the form of a Humanoid to blend in better with non-dragons. Your Humanoid form does not affect your Hit Points or ability scores, and you do not gain any traits associated with the species of Humanoid you choose to turn into. While in this form, you lose your  Drake Jaws, Drake Resistance, and Drake Scales traits, but you gain the ability to don any armor and Shields that your class grants you, and you are able to dual-wield weapons. Each time you choose this transformation option, you transform into the same Humanoid; you decide the species and appearance of this Humanoid the first time you choose this transformation option. The transformation lasts for 8 hours or until you end it (no action required).

You have a base Armor Class of 17 (your Dexterity modifier doesn’t affect this number). You can’t wear Light, Medium, or Heavy Armor and you cannot don Shields.

Your draconic jaws can be used to hold weapons just as dexterously as a Humanoid’s hands. You can use your mouth to interact with objects, perform Somatic components, and hold weapons. When you do so, you ignore a weapon’s Two-Handed property, and you can perform Somatic and Verbal components even while holding a weapon in your mouth, but you are unable to dual wield.