Completing the 706 may seem bad enough to you, but you probably have a pile of supporting documentation that you need to send with it. If you do, attach whichever of the following documents are applicable in your decedent’s estate to the return when you file it.
Consider preparing an index, or list, of exhibits. Attach the index directly behind the 706 and label each of the documents on its face as Exhibit A, Exhibit B, and so on. Using index tabs for each exhibit is also a terrific idea.
Also, when referring to each of the attached documents in the 706, give them specific names (such as Exhibit A, Exhibit B, and so on) for clarity. The clearer you make things for the IRS, the happier it’ll be as it reviews your tax return (and the more comfortable it’ll be that you’re disclosing everything).
Among the documents to attach to the return are
A certified copy of the decedent’s death certificate (required in all cases).
A certified copy of the will, if the decedent died with a will. You obtain certified copies of the will from the court where the will was filed for probate. If you’re unable to get a certified copy, attach an uncertified copy and explain why it’s not certified.
A certified copy of your appointment as executor or letters testamentary.
An IRS Power of Attorney (Form 2848).
Receipt for payment of state inheritance or estate taxes.
Appraisals of property.
Life insurance statements (Form 712). See the discussion of Schedule D.
Gift tax returns (Form 709).
Certificates of Payment of Foreign Death Tax (Form 706-CE).
Copies of trust documents.
For closely held businesses, earnings statements and balance sheets.
If the decedent was a U.S. citizen but not a resident, you need to attach the following additional documentation:
A copy of the property inventory and schedule of liabilities, claims against the estate, and administration expenses as filed with the foreign court, certified by the appropriate official of the foreign court
If the estate is subject to a foreign tax, a copy of the tax return filed under the foreign death tax act, whether estate, inheritance, succession, legacy, or otherwise