When a specified action is performed on a worksheet with the help of a collection of code known as a VBA Subroutine. It also helps to read an external file, also it can open other applications from Excel. A large piece of code can be broken into small parts so that we can manage it easily. Let’s learn why to use submarines:

• Converts large piece of codes into small parts so that the computer ignores all kind of complexities that arises because of large codes
• Reusability of code suppose we in a program have to access the database frequently so instead of writing the code again and again we can create a function to access the database
• Subroutines are self-documenting functions which means a coder can easily say what the program does by looking into the name of the function 

Naming Rules of Subroutines

• It can start with a letter or an underscore but it cannot start with a number or a special character.
• It cannot contain any space in the name.
• The name of the subroutine cannot be a keyword like Private, Sub, End, etc. 

Syntax

Private Sub function_name( ByVal arg1 As String, ByVal arg2 As String)

End Sub

Syntax Explanation

How to call Sub in VBA?

Step 1: Select the developer tab and click Insert drop-down list from the control box.

 

Step 2: Choose the command button from ActiveX Controls Box.

 

Step 3: Draw the command button in the excel sheet.

 

Step 4: Press Alt + F11 to open the VBA code.

Step 5: Write the following subroutine with the name “display” which will display a name in the message box once its function gets called.

 

Step 6: To call the subroutine we need to right-click on the command button and then select view code.

 

Step 7: Write the following code to call the display function by clicking the command button.

 

The following code displays the overall code of the program.