Accident damage: expert opinion, rapid service or estimate?

Hello everyone, my question I have already asked in the 3 forum and there the tip get here once again to ask for. It is about an accident damage and its evaluation, or evaluation, in order to have a corresponding legal certainty, so that everything is handled to my satisfaction. Here is the situation: when I parked out, I was driven backwards in front of the left against the rim and the front apron. I was almost right next to it, but when I noticed it It was already too late to make it. At the front apron on the side below the headlight there are clear scratching and grinding tracks to recognize and on rim and tires are also imprints. I would estimate the driven speed at max. step speed, it was not easy to roll against. From the causer I have all personal and insurance technical data. Now to my actual question: the traces on the front apron are clear, what possibly with I can’t say that when driving, you don’t notice at least anything. What is enough for the insurance as a damage report and how do I best behave? Is a cost estimate from a workshop enough or does the insurance only count against an official report? It’s years since I somehow had to come to “my money” in the way, maybe someone can tell me how this is dealt with.