The Kotlin standard library includes numerous FUNCTIONS that aid in the execution of a block of code within the context of an object. When you use a lambda expression to call these functions on an object, temporary scope is created. These functions are referred to as Scope functions. The object of these functions can be accessed WITHOUT knowing its NAME. Scope functions make code more clear, LEGIBLE, and succinct, which are key qualities of the Kotlin programming language.

Following are the different types of Scope functions available in Kotlin:-

• let:- 
  Context object:   it 
  Return value:   lambda result
  The let function is frequently used for null safety calls. For null safety, use the safe call operator(?.) with ‘let'. It only runs the block with a non-null value.
• apply:-
  Context object:  this
  Return value:   context object
  “Apply these to the object,” as the name suggests. It can be used to operate on receiver object members, primarily to initialise them.
• with:-
  Context object:  this
  Return value:   lambda result
  When calling functions on context objects without supplying the lambda result, ‘with' is recommended.
• run:-
  Context object:  this 
  Return value:   lambda result
  The ‘run' function is a combination of the ‘let' and ‘with' functions. When the object lambda involves both INITIALIZATION and computation of the return value, this is the method to use. We can use run to make null safety calls as well as other calculations.
• also:-
  Context object:  it
  Return value:   context object
  It's used when we need to do additional operations after the object members have been initialised.