De or het indoping?

The correct Dutch article is:

de indoping

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

How to use indoping

the indopingde indoping
this indopingdeze indoping
that indopingdie indoping
our indopingonze indoping
your indopingjouw indoping
every indopingelke indoping
which indoping?welke indoping?
a big indoping / the big indopingeen grote indoping, de grote indoping