So sorry to hear -- my deepest condolences to you and your family on your loss.
It really depends on how complicated her assets were. If your residence is held as joint tenants, you really don't have to do much right away. If bank/investment accounts are joint, you can inform the financial institutions in good time. First thing to do though, is make sure you get a bunch of official copies of her death certificate. Ask for more than you think you'll need, start with 20. If her name is on a lot of accounts, ask for more. It's easier to get them up front than have to go back. If she was taken to a hospital, they will have informed Social Security. If she had life insurance, contact the insurers. They're usually pretty easy to deal with since they do this all the time. You can file the will with the county clerk, or whoever takes care of that in your jurisdiction. And if probate is necessary for any assets which weren't jointly held, they can guide you through what you have to do. My sister and I did this for our aunt, only one of her accounts was in her name only, so we had to inform our cousins. But since our aunt had lived with us for almost 50 years, they didn't pursue anything, which made things easy.
Your banks will want the death certificates, and they'll update any accounts. If any were in her name only, they'll likely freeze it. You can inform your town to change the deed on the house, but in all honesty, there's no rush for that. Real estate people do that all the time when the time comes to sell the house.
Our prayers are with you