Bitcoin-Qt is a desktop wallet you can use for payments. If you’re a merchant or need other payment services you can also use its server utility.

Bitcoin-Qt is often described as the “official" wallet client of the Bitcoin network. It’s developed and promoted by Bitcoin Foundation, the non-profit organization focused on bringing together core BTC developers and guiding the community's contacts with corporations and governments. 

If you’re curious, you might even be able to stop by a physical location since Bitcoin Foundation branches are in dozens of countries around the world.

The infamous and still anonymous Satoshi Nakamoto released the first wallet program called Bitcoin-Qt in 2009 as open source code -- that’s why sometimes it’s called the "Satoshi client.”

Since that time, of course, there have been many changes. One of the more significant ones was the hardfork split led by Roger Ver, who created Bitcoin Cash. This led the BitcoinQT to rename BitcoinQT, into "Bitcoin Core" as of version 0.9.

Thankfully, even though Satoshi Nakamoto went anonymous, he/she/it passed the torch of decision making and changing the code of the official version of the wallet to Gavin Andresen.

In 2014, Gavin Andresen passed that responsibility to Vladimir van der Laan. But changes are not a sole decision, since the main developer agrees with other developers of the kernel: Jeff Garzik, Gregory Maxwell and Peter Wooll.

Also, even though BitcoinQT was created a decade ago, these core developers are constantly working to implement technical innovations and updates to improve the wallet. 

If you choose to use BitcoinQT, keep in mind that it will take a while to complete long synchronization. That’s for your safety though, so you can safely use the BitcoinQt wallet.