This can be done using any of the below methods −
In the Tools window → Navigate to Service menu → you can add a new row
This can also be done by using T-Code SE11 → Select the relevant table. Navigate to Table Content → Display
Make sure Debug mode is ON. Click on Pencil to get Edit mode.
Type Edit in Value column to edit the table in Debug mode. Press F8 (Continue).
Note that for edition it is EDIT and for deletion, it is DELE as shown in below snapshot.
This will open the record. You can change the value and save it.