Necessary or Neccessary? Which is the correct spelling?

Necessary is the correct spelling of the word that something is required or essential.  Neccessary is incorrect and should not be used in English. 

It is necessary to wear a uniform to school.

Why is it always necessary to stop walking when you need to drink water?

Necessary meaning

Necessary means “needed to be done”. It is usually used as an adjective but can also be used as a noun to mean something that people need to survive.

It is necessary to open the bottle before you drink the water.

Food and water are necessaries for people all around the world 

“Necessary” can sound a little formal in certain contexts as it is more common to use the verb “to need” in spoken English.

You need to open the bottle before you drink the water.

Is necessary or Are necessary?

Is necessary or are necessary depends on whether the verb or noun before necessary is singular or plural. 

One car is necessary to fulfill the order

Six cars are necessary to fulfill the order.