Normally every Official document in SAP has either Internal Number or External Number Range Internal being dynamically assigned by system and External, user will populate it based on the Number Range assigned. When we deal with Project System, we Create a Project as part of the Structures which has a certain mechanism to define Project. In SAP S4HANA PS ( ECC-PS), this is called as PROJECT CODING MASK Project Coding mast has two parts PROJECT ID PROJECT ID: This is the Length of the Coding. This can range from 1-5 characters based on your requirement. The Characters in this field would be the start of your Project Definition. For example if you enter the Project ID as ABC... Your Project definition would start with ABC and following by Coding Mask. There is a dependency on the Special Characters. CODING MASK: This controls the total length of Project. This is built by Alpha numerical or Numerical. "X" denotes an Alphanumerical Character and "0" denotes a Numer