If you want to leave a legacy to a stepchild, or a child in a blended family that you have not officially adopted, you must do it via a will or a trust. You need to have an effective estate plan in place if you wish to have your stepchildren inherit anything from you.
If you lack a will or a trust, then under Michigan law, a stepchild or a non-adopted non-biological child will not inherit from you.
This video helps explain why a properĀ estate planĀ is necessary if you want to leave a legacy to your children that happen to not be your biological children.