In Arizona, probate gets started when the person who wants to be appointed as personal representative files the Will (if any) and a petition with the probate court.
The court will appoint the person named as executor (personal representative) in the Will, unless there's a good reason why that person can't or shouldn't serve. If there's no Will or the Will doesn't name a personal representative, the court turns to state law, which lists who has priority for appointment.
Who may be the personal representative:
You are over 18 years of age, and
The surviving spouse of the decedent, or
An adult child of the decedent, or
A parent of the decedent, or
A brother or sister of the decedent, or
A person entitled to property of the decedent, or
A person who was named as personal representative in the Will.
The court determines the validity of the Will and gives the personal representative “letters of administration” which give the personal representative's right to manage the estate.
Next, the personal representative notifies inheritors and creditors about the estate administration. The personal representative notifies inheritors within 30 days of death, The personal representative publishes notice to creditors in a local newspaper for three weeks, and mails notice to all known creditors. Creditors must make claims within four months after the notice is published. Known creditors who received mailed notice can make claims within 60 days of the mailed notice, even if it falls outside the four-month period.
After notice, the personal representative gathers all the assets of the estate. The personal representative inventories, manages, and protects these assets. After creditors have been paid, the personal representative then distribute the assets to the beneficiaries, and closes the estate by filing a petition for closing with the court.
The court uses formal probate to resolve an estate’s legal issues – for example, if the validity as a will is contested, there is a dispute over who should be appointed personal representative, or there are conflicting with interpretations of a will. A Will contest might happen because there are two Wills, and the court must determine which of the Wills is valid.
On the other hand, is there a change to the Will (codicil) that raises the contest to the validity of the Will? Do the contestants allege a fraud, undue influence or other in proper doing?
If the parties can not settle these issues among themselves, they will have to be brought before the court in a formal probate proceeding.
There are other reasons formal probate may be required. The issues are mostly complicated, and a competent probate attorney can help you to determine which form of probate you should file.