How to make player able to fly on right click on use of item

[Rob Boss]

I want to make the player to fly when I right click on any block with an item 

I am new to modding 

[Alpvax]

What do you mean? that you want the player to be able to have creative  style flying when you activate an item? Or more like how fireworks work with elytra?

You need to override Item#useOn (for using on a block) or Item#use (for using the item on air (and possibly blocks with no right click action, I can't really remember)).

For the first approach, you need to set Player#getAbilities().mayfly to true (mojmap mappings). Remember to set it back to false when you want to stop.

For the second approach, you need to get the current Player#getDeltaMovement(), add a vec3 to it (either just a y component for straight up, or based on the Player#getViewVector() for "forwards")