Log on data to an SAP system can be transferred via the secure area of a message.

Go to the message concerned via the start screen and click on „Maintain SAP Log on data“:

A new browser window of the SAP Service Marketplace opens. Your S-User used must have the authorization to maintain system data for the installation number in question.

As the secure area of the SAP Service Marketplace is used here, only access data for installations maintained in the SAP Service Marketplace can be saved. Detailed instructions on how to maintain the access data can be found here:
SAP note 1773689 “How to add logon data securely to an incident – SAP Support Portal