We cannot be sure what shipping service the seller will use. If the item comes from Asia and it's a big or more expensive item, they tend to use DHL or EMS. If it is a cheaper or smaller item, they just use standard shipping. So basically if it's something like a watch or pencils, it would come in the mail into your mailbox (unless the seller uses an expensive and faster shipping method). If you are buying something like headphones, a laptop, or a camera from Asia it's more possible that they use EMS/DHL.
If your item is coming from the USA, it is more likely that the seller would use UPS/Fedex.
The only way to be sure is to message the seller and find out. You can also ask them to use a shipping method of your choice and most of the time, they agree.