How to edit picture?
You don't say which operating system you are using.
Photo Editing requires Photo Editing Software.
To do basic photo editing (cropping, rotating, flipping, adjust brightness, adjust contrast, adjust image size, adjust colo(u)r, adjust exposure, adjust size, adjust red eye) you can use free, built-in software that comes bundled with Windows and Microsoft Office such as: Paint, Microsoft Picture Viewer and Windows Photo Gallery.
In increasing order of editing functions:
Windows Photo Gallery: Fix > Auto Adjust, Adjust Exposure, Adjust Colour, Crop Picture, Fix Red Eye
Microsoft Office Picture Viewer: Picture > Brightness & Contrast, Colour, Crop, Rotate, Flip, Red Eye Removal, Resize, Compress.
Paint: Image > Flip/Rotate, Resize/Skew, Crop, Invert Colours, Adjust Attributes, Clear Image, Opaque.
In Paint you can also use additional tools to manipulate the image or add or delete shapes, text and colour (with a selection of writing or drawing implements): Free Form Select, Select, Fill with Colour, Magnifier, Brush, Text, Curve, Polygon, Rounded Rectangle, Ellipse, Rectangle, Line, Airbrush, Pencil, Pick Colour, Eraser/Colour Eraser.
In Windows Photo Gallery you can view and edit the same image in either of these 3 programs by clicking Open.
For more advanced photo editing, you can use the bundled software that comes with digital cameras such as:
Adobe Photoshop Elements
For more advanced, professional standard photo editing you must buy expensive Photo Ediiting and Graphic Design software such as:
I hope this helps.