How is the disposition of property upon death (will, joint will, agreement on succession) drawn up?

Apart from in a limited number of special cases (Articles 4:97-107 Civil Code (Burgerlijk Wetboek)), a will can be drawn up only by notarial deed or by handwritten private deed handed over to a notary for safekeeping (Article 4:94 BW).
A will made by two or more testators is not accepted (Article 4:93 BW).
An agreement concerning a future inheritance is also not accepted.
According to Article 4:4(2) BW, agreements intending to dispose, in whole or in part, of a not yet devolved estate are null and void.