You get letters of administration from the probate court. In New York, this court is called the Surrogate’s Court. You can have an attorney assist you with the process.

Here is the list of documents you need to apply for letters of administration:
The petition formally requests that the court appoint an administrator for the estate and provides key details about the deceased, heirs, and estate assets and debts.
The proposed administrator signs an Oath and Designation to swear to faithfully carry out their duties and designate a county for legal purposes.
The original or certified copy of the death certificate proves the death officially occurred.
This helps demonstrate payment for the funeral.
This is executed by the distributees, the persons entitled to inherit from the decedent under EPTL § 4-1.1. Any persons with equal or higher priority to serve as administrator sign this to waive their rights. If the distributees do not sign this document, you would have to ask the court to issue a citation.
The court issues citations to notify interested parties of the administrator appointment hearing. Citations are issued to those distributees who do not execute waivers.
There may be additional notice requirements depending on the specifics of the case.
An affidavit of sole heirship is executed by a disinterested person when the decedent was survived by no heir, one heir, or where the surviving heirs are related to the decedent through a person who is also deceased. Sometimes it needs to include a family tree chart.
The petitioner swears they made diligent efforts to find any other potential heirs.
Additional affidavits and documents may be necessary regarding estate facts, assets, debts or special circumstances. After your attorney submits the documents, the court will review the documents and will verify that you are the closest living relative. The court will also make sure that you are the relative with the priority to be appointed the estate administrator.
The petitioner’s attorney drafts this document for the judge’s approval, outlining the appointment of the administrator and their powers and duties. If the Judge of the Surrogate’s Court deems you to qualify, the judge will issue the Decree and Letters of Administration.
How long it takes to get Letters of Administration depends on many things. The most important factor is what part of New York you are filing in. Upstate New York, it can take less than a month to process your application. In New York City, it can take sixty days for the court to even begin reviewing your application, and it typically takes a few months to get letters of administration.
Because of budget cuts and staff shortages, we’ve seen longer wait times for getting letters of administration throughout the court system.
If there are issues with your eligibility to becoming the estate administrator, then getting letters of administration can take years and may not even happen at all.
You often need more than one certified copy, since each bank and government agency would require an original. Also, since some institutions require a more official-looking document, the court can issue a Certificate of Appointment of Administrator. It’s printed on watermarked blue paper and looks similar to a death certificate, birth certificate, or marriage certificate.
Here is a redacted image of a Certificate of Appointment of Administrator obtained by our law firm:

To obtain Letters of Administration, our attorneys will:
It typically takes a few months to receive the letters after filing. We help expedite the process and resolve any disputes or complications
If you would like legal representation in obtaining Letters of Administration, we at the Law Offices of Albert Goodwin are here for you. We have offices in New York City, Brooklyn, NY and Queens, NY. You can call us at 212-233-1233 or send us an email at [email protected].
Sources:
Because there is no will naming a fiduciary, New York law determines who has the right to serve as administrator. SCPA 1001 sets the order of priority among the decedent's distributees:
When more than one person shares the same degree of relationship, such as several adult children, each has an equal right to seek appointment, and the others must be given notice and an opportunity to consent or object. If those with priority renounce or are ineligible, the right passes to the next class. Where no eligible distributee will serve, the Public Administrator of the county may be appointed.
Certain persons are disqualified from serving under SCPA 707, including infants, incompetents, felons, and persons the court finds unfit due to dishonesty, substance abuse, or want of understanding. Non-U.S. citizens who do not reside in New York generally cannot serve alone and must be joined by a New York resident co-fiduciary.
The petition for letters of administration must be filed in the Surrogate's Court of the county where the decedent was domiciled at death — not necessarily where they died or owned property. Each county's Surrogate's Court has its own clerk's office practices and local preferences for documentation.
Filing fees under SCPA 2402 are based on the size of the estate, ranging from $45 for very small estates up to $1,250 for estates of $500,000 or more.
Because the administrator was not chosen by the decedent in a will, the court often requires the administrator to post a bond (a surety undertaking) under SCPA 805 to protect the estate's creditors and distributees. The bond amount is typically set based on the value of the estate's personal property plus anticipated income. A bond may be reduced or waived where all adult distributees consent in writing, where the estate is restricted so funds cannot be withdrawn without court order, or in other circumstances the court allows. We routinely help clients obtain consents and structure the petition to minimize or eliminate bonding costs where appropriate.
If the decedent left personal property worth $50,000 or less (real estate is not counted), the estate may qualify for a simplified voluntary administration, or "small estate" proceeding, under SCPA Article 13. A voluntary administrator is appointed through a streamlined affidavit process, avoiding the cost and delay of a full administration proceeding. We can evaluate whether your situation qualifies for this faster alternative before you file for full letters of administration.