After a death
After a person dies the legal steps needed can be confusing. It can be confusing because there's you can own an asset in various ways - for example - sole ownership, joint, in a trust, by contract (life insurance, etc), pensions, IRAs, POD... You get the picture.
It's important to understand that the steps needed is determined on an asset by asset basis - dictated by the rules of ownership involved. Don't confuse these rules of transfer with the tax laws - they are not the same. For example, joint assets become the property of the surviving joint owner without probate but 1/2 of the joint asset is part of the deceased's gross taxable estate. (Put simply, no probate but yes tax!)
Then there are two types of taxes to consider, both income and estate taxation. Even if the estate is under the amount subject to estate taxation ($1 million MA, $5,430,000 Federal) these tax rules make a difference in the post death steps.
A will and trust can determine who gets what when the type of ownership in sole in a person's name (will) or when the particular asset is in a trust (trust ownership before death). When the asset is placed into trust name before death, this is called 'funding' the trust with that asset.
If all a person's assets are in a trust before death, this can 'avoid probate' of the will. This is important to some people, as the media has made much of the time delays whenever a court proceeding (read 'probate in Massachusetts') is involved.