Are you wondering how to spawn Awsome fireworks,
With commandblocks?
Then stop searching!
I'm Gonna learn you how to do that!

Step one: A regular Rocket-Entity!
 
Type/Copy&paste this Command in your Commandblock:

    /summon FireworksRocketEntity ~ ~ ~ {LifeTime:20}
  All that Basically does is spawning a Firework Rocket, The tag {LifeTime:20} Is how long the rocket fly's in Ticks.

Step two: Adding Effects!

Type/Copy&paste this Command in your Commandblock:

/summon FireworksRocketEntity ~ ~2 ~ {LifeTime:20,FireworksItem:{id:401,Count­:1,tag:{Fireworks:{Explosions:[{Flicker:­1,Trail:1,Type:1,Colors:0],FadeColors:[­0]}]}}}}

This command spawns a FireworkEntity With a Ball Effect The effect is Customizable but ill tell you more about that later.

Step three: Multiple Effects!

Type/Copy&paste this Command in your Commandblock:

/summon FireworksRocketEntity ~ ~2 ~ {LifeTime:20,FireworksItem:{id:401,Count­:1,tag:{Fireworks:{Explosions:[{Flicker:­1,Trail:1,Type:1,Colors:0],FadeColors:[­0]},{Flicker:1,Trail:1,Type:2,Colors:[16­777215],FadeColors:[16777215]},{Flicker:­1,Trail:1,Type:3,Colors:[15000],FadeColo­rs:[15000]}]}}}}

This spawns An effect IN a Effect. You can FULLY Customize This! Its really usefull for Firework Shows!

Step Four: Direct Explosion!

Type/Copy&paste this Command in your Commandblock:

/summon FireworksRocketEntity ~ ~0 ~ {LifeTime:0,FireworksItem:{id:401,Count­:1,tag:{Fireworks:{Explosions:[{Flicker:­1,Trail:1,Type:1,Colors:0],FadeColors:[­0]},{Flicker:1,Trail:1,Type:2,Colors:[16­777215],FadeColors:[16777215]},{Flicker:­1,Trail:1,Type:3,Colors:[15000],FadeColo­rs:[15000]}]}}}

You can do this with every previous Firework-Spawning-Command. Just set the Tag {LifeTime} To 0,
That forces the Entity to Explode directly! Just like in Hypixel Maps!

Types for the Type tag!

0= Small Ball
1= Large Ball
2= Star
3= Creeper Face
4= Burst

Colors for Coloring youre firework!

White: 14540253
Orange: 14384446
Purple: 11751612
Light Blue: 7047881
Yellow: 11642407
Lime: 4304440
Pink: 13665433
Gray: 4210752
Light Gray: 10133921
Cyan: 3042953
Purple: 8273333
Blue: 3029133
Brown: 5190175
Green: 3491355
Red: 9843760
Black: 1644054

Thank you for reading!
If you have any suggestions leave them in the comments!
If i made Mistakes please say it.
Sorry for my English its not very good!
Bye!