Do I need to submit any docs [Sponsorship] b4 VISA interview ? How?

My parents have an appointment in March. We have filed all the application DS-160 etc. But while scheduling the appointment, we never came accross any information for submission of these documents . I remember for earlier VIS before 10 years we had submitted the sponsorship letter etc sent by my brother prior to the appointment through Pune office of the counsulate.

Has the process changed ? or I am going in wrong manner?

Now there is no need , nor provision to submit any document before visa interview.

There have been lot of changes in procedures.

Follow the system