It all depends on how that party registered the LLC TAX MATTERS to be handled.  If their original application chose as a Corporation, then you would first complete the 1065 and it will generate a K1 for you to use when filing their personal income tax.  You would then go onto a 1040 application and enter the K1.. it will generate the forms needed to complete their taxes.. such as a schedule C/SE etc..    BUT if they chose in the beginning to file as a Sole Prop on a Sch C,  you would NOT do a 1065 at all.   Hope this helps!