fill forms pdf with okular

I had some pdf files and need to fill the forms in them. I tried evince, openoffice and okular, and found okular is the best !!

1) evince: we can fill in the contents, but we can not save them !
2) openoffice: we can also fill in the contents and can save it. But open office can sometime change the format of forms and it is not clean !
3) okular: it is very effecient and easy and clean ! when we open a pdf form with okular, in the topside it appear an option: affichier les fomulaires (show the forms) or cachier les formuliares (hide the forms). If we choose the first, we can fill the forms. Then if we choose the second, the contents that we have filled will be conserved in the form and can not be modified, except we click on the "affichier les fomulaires" again ! With this tool we can save the filled forms and print it.