spouse died has plan
So sorry to hear about your loss. Hopefully the retirement plan can help support you and make this an easy transition. I would start by finding the most recent statement for the account and calling the phone number on that statement. You could also try calling the employer who sponsored the plan if you cannot find a statement. Generally it is a fairly simple process. They will send you some paperwork and usually request a death certificate for their records. As you get into the process feel free to ask for help as I'm sure there are plenty of people here that can steer you through the process.
Everyone that enrolls in a company's retirement plan is required to complete a beneficiary form. The person that runs human resources for the company should have a copy of this form on file. As soon as they learn of the death, they will set in motion the steps to distribute the proceeds in conjunction with the record-keeper, administrator and consultant for the plan. I hope this helps and I'm sorry for your loss.
Call plan, get direction.