Learn Dutch: Het is noodzakelijk om deze regels in te voeren. - It is necessary to introduce these rules.

The base verb here is invoeren (to introduce or implement), which is a separable verb. When a separable verb is used in a te + infinitive construction, the word te is placed directly between the prefix (in) and the verb stem (voeren), resulting in in te voeren.

Is the word om strictly required here?

While sometimes optional in modern Dutch, the om ... te structure is the standard and most natural way to link a phrase like het is noodzakelijk (it is necessary) to an action. The om acts as a bridge introducing the infinitive phrase.

What is the difference between using noodzakelijk and nodig in this sentence?

Both mean that something has to be done, but noodzakelijk is slightly more formal and carries a stronger sense of urgency. Nodig translates closer to "needed," while noodzakelijk translates to "essential" or strictly "necessary."

How would the sentence change if I wanted to make deze regels the subject?

You would say: Deze regels zijn noodzakelijk om in te voeren. Notice that the verb changes from the singular is to the plural zijn to match the new subject (deze regels).