People have to send what they sell themselves, usually using mail. Some items may be collected by the buyer such as items to large or heavy to post. Buyers can transfer the money in any way they want as long as the sellers accept payments made that way. A lot of people use PayPal to transfer the money. PayPal is owned by the same people as eBay. Margaret Whitman was the CEO of eBay from 1998 to 2008.
eBay was started in 1995 by Pierre Omidyar. It was first called Auctionweb. The name 'eBay' came later when he tried to register a domain name for his planned name EchoBay. It was already taken so he shortened the name to 'eBay'.
Millions of items are bought on eBay every day. It is often very cheap to list an item on eBay. Total costs are usually below ordinary auction house costs. Many people look at others' items because they are interested in them.