That would be a textbox in form Footer section with an expression as ControlSource.
For Delsumma:
=Sum([your field name here])
Aggregate functions must reference fields, not controls.
For Totalsumma, probably like:
=tbxDel + tbxLeverans + tbxRabatt + tbxMoms
If you need more help, we need more details.
This is really basic Access functionality. Any introductory tutorial book should explain this. Have you studied one?
How to attach file: http://www.accessforums.net/showthread.php?t=70301 To provide db: copy, remove confidential data, run compact & repair, zip w/Windows Compression.
If the field you're trying to sum is calculated on the form:
=Sum(FirstField * SecondField)