If you use other SAP Systems, most of your data will probably come from those systems. However, you can also enter data directly into the FI-SL System when necessary.
You enter documents into the FI-SL System when you want to:
You can also reverse an FI-SL actual document posting.

When you enter data using the FI-SL Actual posting function, other SAP Systems are not affected by the data. Direct entries in FI-SL are marked separately in the FI-SL line item databases, so that you can determine which entries came from other SAP Systems and which were entered directly into the FI-SL System. In the summary database, direct entries made with the Actual posting function are marked separately via the version.
For more information about entering data into the FI-SL System, see
Entering an Actual Document.