Some dealers will provide installation services, but there are also a lot of them that don't, leaving the customers with two options: a DIY install, or the option for a customer to independently hire an electrician to perform the install.
I can't speak for all dealers, however...but most stuff comes via ground shipping, (FedEx / UPS) and if you are getting to the point where you are doing a very large system (Quattro 10kVA inverters for example), there is a point where it's just too heavy and bulky and needs to go on a freight truck.
If I were in your shoes, first, I would try and figure out if you are going to install the system on your own or pay someone to do it. If you are paying someone to do it, you need to first figure out if they will be the one providing the equipment or not (always recommend figuring this out before buying anything on your own, some installers will only put in equipment they provide).
If you are going the DIY install route, it's good to not shop just for low prices, but also which dealer is able to offer support to you at your level if you have a hiccup during the install. It can turn out that one seller is a few bucks cheaper, but their after sale support is nonexistent (a bit of a trap when purchasing on Amazon).