One of my clients sent a 1099 to my old address and I can't get it. Should I file anyway and try to add it on later or something ?
If you don't have a 1099, the best course of action is to file for an extension, and get the proper documentation.
https://ttlc.intuit.com/replies/7398058
If you know the amount of the 1099 you can file as long as you add the amount in. I would recommend filing with the amount added.