Learn Hardcore Dutch: Ik moet het contract ondertekenen.

moet is the present-tense form of the modal verb moeten, which expresses necessity or obligation—equivalent to “must” or “have to” in English.

Why is there no te before ondertekenen (to sign)?

When a modal verb (like moeten, kunnen, mogen, willen, etc.) precedes an infinitive, you do not add te. You say Ik moet ondertekenen, not Ik moet te ondertekenen.

Why is ondertekenen placed at the end of the sentence?

Dutch main clauses follow the V2 rule: the finite verb (moet) occupies the second position, so the non-finite verb (ondertekenen) goes to the very end.

Is the verb ondertekenen separable? If so, where does the prefix go?

ondertekenen is an inseparable verb. The prefix onder always stays attached, even when you add objects or use different tenses.

Why is het contract used instead of de contract?

In Dutch, nouns ending in -ment are usually neuter. Neuter nouns take the definite article het, so you say het contract.

If I replace het contract with the pronoun it, where would I put it?

Object pronouns come before the verb cluster. You’d say Ik moet het ondertekenen (“I have to sign it”).

How would I turn this statement into a question in Dutch?

Move the conjugated verb to the first position and then the subject:
Moet ik het contract ondertekenen? (“Must I sign the contract?”)