If I want to leave a property to my children but the property has a mortgage on it, how do I word it in the Will?

Do yourself and your potential heirs a favor and seek out an estate planning attorney who could prepare a trust with a pour over will, rather than use of a will only; use of a will, will put you into probate court and cost your heirs some significant money in probate fees, whereas if you put the residence into a trust naming the intended beneficiaries, and put the life beneficiary as the trust to pay off the mortgage ammong other provisions, then your heirs will stay out of probate court and pay a lot less fees to the attorney then you would pay in a probate court setting.