The will has to be probated, which means you need to take the will and death certificate and file the appropriate petition to appoint you as executor - the will is just a bunch of "suggestions" until it is deemed valid. Every state has unique procedures for exactly how this is done. I suggest you review the situation with an attorney so you do everything properly.
This is not legal advice nor intended to create an attorney-client relationship. The information provided here is informational in nature only. This attorney may not be licensed in the jurisdiction which you have a question about so the answer could be only general in nature.
To get the necessary "letter" you must go to the Probate Court (sometimes called court of chancery) of the county where your mother resided prior to her death and ask for the necessary forms that you will need to file. You will need to take the will with you (preferably the original, but in some places it is not required), and an original death certificate. You will fill out the forms and ultimately take an oath of office that you will execute (perform) the wishes in your mothers will. This is all part of the requirements to be appointed Executor and have Letters Testamentary or similar "letters." These letters will give you the authority to act on behalf of your deceased mother with any financial institution with which your mother had an account, and empower you to sell her property and distribute her estate as she has stated in her will. It is possible to do this without an attorney, but I recommend you ask the local Bar Association if they have referral list of attorneys who do this for a reasonable rate. You are best served getting legal counsel for your specific situation.
A will must go through probate and validated by the court before it can be acted on. The issuance of a document called Letters is that validation and is required for all estates that exceed $150,000. I suggest you speak with an attorney to learn more about what you have to do.
As my colleagues have stated, you need to submit the will to probate. Go to the Fresno County Superior Court website and you can look up some general information on what you need to do as the executor and how to go about it. Depending on the complexity and size of the estate, you might want to consult with a probate attorney in your area.
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