you can fly up to 30 feet of distance when in dragon form instead of using your walking speed. you cannot fly while you are in your human form.

you can use your dragon tail as if it were a hand while you are in dragon form. you cannot use your tail to grab things while you are in your human form since your human form doesn't have a tail.

you can be ridden as if you are a horse but you cannot use any movement speed other than your walking speed while being ridden.

you use Radiant Ray as your main dragon breath attack and bite weapons as your main melee attacks.

note: equip (A.H.C) Freeze Ray as your main dragon breath attack; equip (A.H.C.) Normal Bite or (A.H.C.) Big Bite as your main melee attack.

you are resistant to Cold damage.

you can read, write, speak, and understand common.

you can read, write, speak, and understand draconic.

you are vulnerable to Psychic damage.

you cannot attack while flying unless your party's Dungeon master says otherwise..

you can use either Hold Monster or Detect Magic three times per long rest:

Detect Magic:

For ten minutes, you sense the presence of magical effects within 30 feet of yourself. If you sense such effects, you can take an action to see a faint aura around any visible creature or object in the area that bears the magic, and if an effect was created by a spell, you learn the spell’s school of magic.

The spell is blocked by 1 foot of stone, dirt, or wood; 1 inch of metal; or a thin sheet of lead.

Hold Monster:

Choose a creature that you can see within 30 feet of you to freeze with breath of cold in the attempt to paralyze it. The target must get a higher on a constitution saving throw than you or have the paralyzed condition for three rounds. that roll can be rerolled on each turn the target takes while it is paralyzed to see if it is freed from paralysis. 

as a bonus action you can move up to half your speed and then do a bite attack.

you can use Freeze Breath as an alternate dragon breath attack to Freeze Ray.

note: to use Freeze Breath, equip (A.H.C.) Freeze Breath

you have blindsight up to 20 feet.

you have dark vision up to 40 feet.

you can walk or run up to 30 feet.

you can use Hail Storm as an alternate dragon breath attack to Freeze Ray.

note: to use Hail Storm, equip (A.H.C.) Hail Storm

unless your dungeon master states otherwise: as a pure dragon, you fear getting hurt while flying over deep places (like a ravine or the ocean.), so you stay on the ground. also, you are used to walking and running rather than flying.

you can use either Shapeshift or Invisibility three times per long rest,

Shapeshift:

You can take an action to shape-shift into a medium beast or humanoid form. you can stay in the new form for 1 hour or until you take a magic action to shape-shift into a different medium sized beast or humanoid form. to shapeshift into a creature, you must have seen it before and it can’t be a Construct or an Undead. your temporary new forms only have your stats and abilities but not your appearance.

Invisibility:

due to you having scales that can bend light, you can take 1 action to turn invisible for 1 hour. The spell ends early immediately after you make an attack roll, you deal damage, or you cast a spell.

you can use either use Zone of Truth or Create or Destroy Water, three times per day,

Create or Destroy Water:

using an action, you do one of the following:

Create Water. You create up to 10 gallons of clean water within 30 feet of you in an open container. Alternatively, the water falls as rain in a 30-foot cube within 30-feet of you, extinguishing exposed flames there.

Destroy Water. You destroy up to 10 gallons of water in an open container within 30 feet of you. Alternatively, you destroy fog in a 30-foot Cube within 30 feet of you.

Zone of truth:

As a action, you create a magical zone that guards against deception in a 15-foot-radius Sphere centered on a point within 60 feet of you. For ten minutes, a creature that enters the spell’s area for the first time on a turn or starts its turn there makes a Charisma saving throw. On a failed save, a creature can’t speak a deliberate lie while in the radius. You know whether a creature succeeds or fails on this save.

An affected creature is aware of the spell and can avoid answering questions to which it would normally respond with a lie. Such a creature can be evasive yet must be truthful.