Got a question about my iPhone 7+?

So I was gonna send my iPhone in because my screen is cracked and my one of my speaker isn't working like nothing is coming out, if I request or whatever I do will they send a envelope first so I can send my phone to apple. Or will they send a new iPhone because I'm just giving it to them to just get a new iPhone 7+ if that's even possible.

Is there another way to find my iphone?

I used phone finder app on my ipad and all it does is list its last location in my house, I searched all over and still can't find it, I called it from a friends phone and I goes to voice mail, the battery is obviously dead, are there any other options besides tearing the house apart, but it does need a good cleaning, guess I will have to search room by room, unless you good people have some advice