Form 1065 & K-1 - ENGAGE CPAs

The 1065 is the business tax return you'll need to file if you own a partnership. This is where you'll show the partnership's business income and any deductible businesses expenses that will be used to reduce that income.
No tax is owed to the federal government at the business level, but partnership income is subject to both ordinary income tax and self-employment tax. Both of those are paid at the individual level, on Form 1040. And the way the partners know how much of the partnership income is theirs for the year is by the K-1s that are produced within Form 1065. A K-1 is created for each partner of the partnership, showing the total taxable income that is theirs for the year. The owner then takes that K-1 and inputs it on their return, so that it's included in their taxable income for the year.
The 1065 is due every year by March 15th, with an option for a 6-month extension. But you can't file your individual tax return without your K-1 from your partnership.