If you want to send a private popup message to specific user then you should use TH_POPUP function on SAP system.

Its very simple and very helpful.

You just need to check following steps ;

SE37 –> TH_POPUP

F8 – Execute

Fill the following areas with following explanations

Client –> Client Number of you SAP system

User –> SAP username which is you want to send your message

Message –> Message Body Area

F8 – Execute

Let’s check the user’s screen ;