Install SAP GUI Scripting API: Ensure that SAP GUI Scripting API is installed and enabled on the machine where you will run the PowerShell script. This API allows automation of SAP GUI tasks.

Connect to SAP: Use PowerShell to establish a connection to the SAP system using SAP GUI Scripting. This involves creating an SAP session object and connecting to the appropriate SAP instance.

Navigate to the Invoice Processing Transaction: Once connected, navigate to the transaction code or menu path where invoice processing is performed.

Automate Invoice Processing Steps: Use PowerShell to simulate user actions such as entering invoice details, verifying data, and submitting the invoice for processing. This may involve interacting with SAP GUI elements such as input fields, buttons, and menus.

Handle Errors and Exceptions: Implement error handling in your script to deal with unexpected situations, such as network errors, SAP GUI errors, or invalid input data.

Close SAP Session: After processing invoices, gracefully close the SAP session to release system resources.

The PerformAutomatedChecks function is added to encapsulate the logic for performing automated checks for mismatches and discrepancies in invoice data. You should implement this function according to your specific requirements.

The Test-FileExists function is introduced to check for the existence of the invoice file before processing it. You can modify this function as needed to check for other required files or resources.

The script now checks whether the automated checks for mismatches and discrepancies pass before proceeding with invoice processing. If the checks fail, the script aborts the invoice processing and outputs an error message.

Before processing the invoice, the script checks for the existence of the invoice file. If the file is missing, the script outputs an error message and aborts the invoice processing.