Do you have letterboxes in the USA in front of your house? ?

In some places, we do.  In some places, we have a mail slot in the front door.  In some places, we have a box on the front of the house.  In some places, we have a box on a pole along the street.  In some places, we have a bunch of boxes for several houses clustered all together.  In a few places, mail isn't delivered to every house and instead everyone goes to the post office to pick it up.

Not mine but I live in an apartment.

We would call them mail boxes. 

Most houses have them at the end of their driveway, so the mail person can stay in their vehicle to deliver the mail. 

Out in the county you can find groups of mail boxes at the road side. So the mail person doesn’t have to drive miles to each farm/house.

Townhouses can have a big metal box with several mail boxes in it for the street.

Apartments can one to two locations of small boxes for tenants to get their mail.

When I was growing up we had our mail box on the front porch.  Many home still do. But the post office is trying to get all Mail boxes at the road side.

A mail person driving to deliver mail is much more efficient than walking the route.

Some places do and others don't. Where I live, the mailboxes aren't in front of each house. There are a cluster of mailboxes every couple of blocks where mail is delivered.

Every house has access to mail delivery at that location (except maybe extremely rural areas.)  That can be an individual box on the street, a group of 2-10+ boxes (either individual or secured) somewhere on the block within easy walking distance, or a slot in the door.  People also have the option of purchasing boxes at the post office for a fee and using those.  

Some neighborhoods have a one spot for several houses. Mail is deliverable to every address.

Most of us have a mailbox on a post situated on the road in front of our houses. In most suburban and rural communities, the postal carriers drive and lean out the window to put mail in the boxes. There are some communities in my city where the houses are closer together, and the mail carrier walks from house to house to put mail in post boxes attached to the house. In most apartment buildings, there's a central area with mailboxes that the residents open with a key. And in a few rural places where the houses are really far apart, there may be one group of mail boxes at an intersection, and people have to drive there to get their mail. 

We have mailboxes, which mailmen deliver our mail into. If you want to send mail you can put it in the mailbox or attach it to the mailbox with a postage stamp on it.