What is Photoshop?
Adobe Photoshop (adobe.com/products/photoshop.html) is a paid image editor available for Windows and Mac, capable of photo editing, graphics design, and animation. It's one of the world's most famous software.
Photoshop used to be sold as an one time purchase, but currently it's sold as a subscription model. This has lead users to search for alternatives. An one-time purchase alternative for Photoshop would be Affinity Photo. Free alternatives include Krita and GIMP.