My husband passed at the end of last month. He has 1099 w/write-offs, receipts, etc., plus SS, & w2's I have to find. How do I file extension w/o all info?

When filing an extension, you only need to include his name, address and SSN even when deceased and a payment of the estimated amount due.  If you believe there will be an amount due, the best thing to do is to estimate.  Depending on the amount of write off's he has, you may be best to make a payment based on his 1099 income, SS and W2's without the deductions.  This may have you pay more than is owed, then when you actually have all of the receipts you would be able to file and claim a refund of the payment you make with the extension.  In general, it is better to overpay, then to underpay so you can avoid a penalty. If you have some receipts, this will allow you to get closer to the actual amount that will be due.