SAP systems are client systems. The client concept enables parallel operation, in one system of several enterprises that are independent of each other in business terms. In organizational terms, a client is an independent unit in the system. Each client has its own data environment, including its own master data, transaction data, and assigned user master records.

To log on to an SAP client system, you must have a master record, associated with your user ID, stored in the client system.
The following table lists the details that you must provide at the time of log on:
Field | Description |
---|---|
Client | The client system that you want to access. The client number appears by default. |
User | The unique ID that you need to log on to an SAP client. |
Password | The secret combination of alpha-numeric characters or symbols that will help protect your user ID from unauthorized access. Note that the password at the time of entry is masked with asterisks for security reasons. |
Language | The language in which you want to view your SAP system. The default language is the system default language. |
Multiple log ons are always logged in the system for security as well as licensing reasons. If you attempt to log on more than once, a warning message appears, as multiple log ons are not recommended.