De or het visumverlening?

The correct Dutch article is:

de visumverlening

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

How to use visumverlening

the visumverleningde visumverlening
this visumverleningdeze visumverlening
that visumverleningdie visumverlening
our visumverleningonze visumverlening
your visumverleningjouw visumverlening
every visumverleningelke visumverlening
which visumverlening?welke visumverlening?
a big visumverlening / the big visumverleningeen grote visumverlening, de grote visumverlening