De or het bestelcode?

The correct Dutch article is:

de bestelcode

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

How to use bestelcode

the bestelcodede bestelcode
this bestelcodedeze bestelcode
that bestelcodedie bestelcode
our bestelcodeonze bestelcode
your bestelcodejouw bestelcode
every bestelcodeelke bestelcode
which bestelcode?welke bestelcode?
a big bestelcode / the big bestelcodeeen grote bestelcode, de grote bestelcode