Assigning an SAP User ID to a Personnel Number
You can assign an SAP user ID to a personnel number using the Communication infotype (0105), subtype System user name (0001).
Enter a personnel number.
In the Direct selection section, enter 0105 in the Infotype field, and 0001 in the Subtype (Sty) field.
In the Communication section, enter the SAP user ID in the ID/number field.
You have assigned an SAP user ID to a personnel number.