What to do if you’re left money in a will

Looking to speak to a financial planner or lawyer who specializes in wills/end-of-life requests. If someone is left money in a will, how do they get it? Do they pay taxes on that gifted income? What should they do if they receive a large sum of money? Are there any steps they need to take (or avoid) to make sure they follow the law and get their money from a will?