If you have a Last Will and Testament, you can use it to state your final wishes about your property and heirs, and name your estate executor. If you are the parent of a minor child, your Will can also be used to name a guardian. There are, however, many things Wills do not cover.
Jointly Owned Property
If you own property in joint tenancy with someone else or in tenancy by entirety with your spouse, you cannot use your Will to leave that property to someone else. You can only leave property that is titled solely in your name.
Because property left in a Will must be titled only in your name, your Will does not cover leaving inheritances titled in the name of a Trust. If you have a Revocable Living Trust, property within the Trust will belong to you at death, but it will not be in your name. For Irrevocable Trusts, the property belongs solely to the Trust, and the Trust agreement will state the beneficiary. Your Will cannot.
Pay On Death Accounts
If you have signed a beneficiary designation form for any retirement, savings or checking account, your Will cannot state a different beneficiary than is on the form. Your Will does not actually cover this type of account, but you could use it to reiterate what is on the account form. You cannot, however, update your beneficiary in any manner excepting through completion of a new designation form.
A Last Will and Testament does not cover the bequeathing of Life Insurance policies. This is because your policy allows you to name a beneficiary. You can choose a person, a Revocable Trust, or an Irrevocable Trust. You cannot, however, name your Will as a recipient of your policy.
If you want to leave anything besides a direct inheritance, your Will cannot help. A Will does not cover special inheritances such as long term distribution of funds for special needs, pets, or charities. You may, instead, use a Trust to leave inheritances with special distribution schedules.