Signing of ABAP List-Based PI Sheets 
Use
You use signatures or digital signatures at the end of PI sheets to confirm that the data entered in the PI sheet is correct and complete.
For statements concerning quality in the manufacturing process, you can enter a comment. If the corresponding settings have been made in Customizing for Batch Records , this comment is included in the PI sheet document and the Deviation document of the batch record. It can be used as a basis for the usage decision.
Prerequisites
A process instruction in which a signature has been specified as an input value has been defined in the PI sheet (see Definition of Signatures ).
The type of signature to be used in PI sheets has been defined in Customizing for the control recipe destination. You have the following options:
Signature without a password check
Signature with a password check
In this case, you must also define passwords for the corresponding users in Customizing for the control recipe destination.
To execute the signature, you may also need a maintenance authorization for the PI sheet, which is defined in the process instruction.
Digital signature
If several individual signatures are to be executed, you also define a signature strategy in the control recipe destination or in the process instruction.
The process instruction can specify whether the signature strategy is carried out
For more information about digital signatures and the required settings, see Approval Using Digital Signatures .
Features
The system processes signatures or digital signature that you use to sign a PI sheet in exactly the same way as signatures that you enter to complete a process step (see Reporting of Actual Data in ABAP List-Based PI Sheets ).
Unlike signatures you use to completes process steps, you can carry out signature strategies in two different ways:
Synchronous procedure
This procedure is carried out by default. All individual signatures must be executed immediately after one another. It is only then that the system saves the signatures and completes the process step.
Asynchronous procedure
You must activate this procedure in the process instruction. It can only be carried out when completing the PI sheet. The system immediately saves each individual signature. You can carry out several other functions in between the individual signatures.