I have to correct the preposition where necessary.

My answers in the brackets.

1. A lot of money was stolen of his wallet. (from)

2. He feels shy with people he does not know. (I think , it is correct)

3. Two of the shirts are missing. (no idea)

4. Before we give an identity card, we need evidence from your address. (of)

5. I have decided not to go in Mumbai. (to)

6. I saw the cat going in the kitchen. (into)

Please check my asnwers.
#2 could be "He feels shy around people he does not know" but I also think that "with" is okay.

Otherwise, they look good to me.
<Two of the shirts are missing. (no idea)>

It's correct.