De or het declaratieregeling?

The correct Dutch article is:

de declaratieregeling

Rule Words ending in -ing: almost always de. See the rule

How to use declaratieregeling

the declaratieregelingde declaratieregeling
this declaratieregelingdeze declaratieregeling
that declaratieregelingdie declaratieregeling
our declaratieregelingonze declaratieregeling
your declaratieregelingjouw declaratieregeling
every declaratieregelingelke declaratieregeling
which declaratieregeling?welke declaratieregeling?
a big declaratieregeling / the big declaratieregelingeen grote declaratieregeling, de grote declaratieregeling