Understanding SAP Transaction Code

Standard SAP Transaction codes consist of four characters.

Each character defines something specific to SAP

The first character defines an SAP module.
The second character defines an area within an SAP module.
The third and fourth characters define a specific transaction within a module or area .Typical values are

01 Create
02 Modify
03 View

For example lets take MM01

M         =>         Material
M         =>        Management
01        =>         Create Material

So MM01 is used to create material.
Similarly MM02 for modifying existing material , MM03 to view materials