Question about buying things in ebay

So I'm planning to buy some bleach key chains soon. This is my first time ever buying a actual physical item through the internet. I got a question since I'm in school and I got football practice after school I won't be home for almost the entire day, will the items be left in my mail box seeing as it's just small key chains? If they're not where can I go to pick them up my friend says to go to the local post office but I'm not sure how to prove to them that I am the actual person who has bought the item. Also what if your paypal address is different? Do they send the items to your home based on your paypal address or ebay address?

 

paypal sends it to your address. strange question.

 

Let me try to re explain I got two addresses one is my "home" address. My friend made the paypal and since then he has moved away I edited the address to show my real home address. I'm wondering if the item gets sent to the "home" address or alt address.