Upon the death of a person that has prepared a Will, their Will will be presented to the Notario and a letter will be given to the heirs documenting that they now own the property described in the Will.
There are certain documents that you may already have in place, like your Fideicomiso and your bank account, that have designated beneficiaries that will be able to take possession of the property or the money in the bank. But without a Will, there may be possessions, like motor vehicles, boats, art, and jewelry, which will not pass the way you would want or expect. The answer is to make sure you have the correct documents in place before you need them.
When it comes to married couples there is no right of survivorship. When the death of one of the couple occurs, an undivided half will be transferred pursuant to either the decedent's Will or pursuant to state intestacy provisions. Without a Will, if there are surviving children, the distribution could find the surviving spouse disinherited.
There is not a consensus of what the law requires so we advise you to get a legal advisor if you have valuable property in Mexico and you want to control what will happen to it in the event of your death. Estate laws are governed by each Mexican state and there are differences among them. Wills are not under Federal jurisdiction so the state laws governing Wills prevail.