A function can be called by passing the function name followed, by a space, and then arguments (if any) separated by spaces, as shown here:

let sum = addValue 3

We can perform many tasks using F# functions, some of which are as follows:

• We can create a new function and link that function with a type as it acts as a variable type:
  let square x = x*x
• We can perform some calculations as well, such as:
  let square x = x*x

• We can assign a value. Taking the same example:
  let square x = x*x

• We can pass a function as a parameter to another function like this:
  let squareValue = List.map square[1;2;3] // using square function

• We can return a function as a result of another function example:
  let squareValue = List.map square[1;2;3]