Well, I was in not that long ago, so I know you do not have to give formal reports to the congregation at all. They do have little householder record slips that they use to record information about you to help them on their return visit. If people are not home they write their number on the slip so someone can call again. There's a little space to write "left tract or magazine, etc" or if the homeowner was home but too busy to talk and said come back later or they are a night worker and don't call during day. Practical stuff like that.
Publishers also have their little field service books where they write down the names of those they talked to or placed literature with whom they plan to call back on. They might write what was discussed, points of interest to you, whether you have kids, work etc. They do not turn this information in to the congregation or share it with others unless they are taking someone with them on return visit and then they may fill them in on the general gist of the previous call. It is just to help their memory and to help them figure out what to say to interest you further on their next visit.
I have never seen them write down negative stuff about people they called on and share it with others. Usually if call is negative they do not call back so have no need to write anything down about it.
Cog