All you need to know about photoshop

Adobe Photoshop is a photo editor developed  for mac OS and Windows OS.

 Thomas and John Knoll created photoshop in the year 1988

Photoshop files have default file extension as .PSD, which stands for "Photoshop Document and  sometimes have the file extension .PSB, which stands for "Photoshop Big" others which include jpg,png,gif etc

Photoshop functionality can be extended by add-on programs called Photoshop plugins (or plug-ins). 

Photoshop tools

Pen tool

Clone Stamp Tool

Shape tools

Measuring and navigation

Selection tools

Cropping

Moving

 And more

for more details about photoshop and the tools click

link

SOURCES:

https://en.wikipedia.org/wiki/Adobe_Photoshop