Business & farm

You can't attach a document to your tax return.   But TurboTax will ask about information from supplemental statements when you enter the K-1.   It is common to have statements included with K-1s, so after you enter the form detail in TurboTax, you will be asked about supplemental information from statements referenced in Box 17 or Box 20.   

Schedule K-1s are issued by pass-through entities (partnerships, S corporations, estates, trusts, and LLCs). These entities don't pay income tax on the profits and losses that are "passed through" to their partners, owners, shareholders, or beneficiaries on Schedule K-1. The recipients then report the K-1 on their own personal tax returns.    TurboTax Online instructions:

• Sign in and open your return by selecting Pick up where you left off under a section.
• Search for K-1 and select the Jump to link at the top of the search results.
• This will take you to the Schedules K-1 or Q screen.
• Answer Yes and follow the prompts. You may be prompted to upgrade to Premier if you're not already using it.
• We’ll ask some questions about your K-1, and then you’ll enter the data from the form.

CD/Download desktop instructions:  

• In your TurboTax program, search for K-1 and select the Jump to link in the search results.
  • In Mac: Select the Federal Taxes tab, then Wages & Income. On the Income Summary screen, scroll down to Schedules K-1, Q, and select Start.
• This will take you to the Schedule K-1 and Schedule Q screen.
• Answer Yes and follow the prompts.
• We’ll ask some questions about your K-1, and then you’ll enter the data from the form.