If you want to change the size, delete, or copy one of the artboards, just use the artboard tool to do it.
If you want to create a new document, you can change the width and height of the document. You can also change the name, units, and what color mode you want.
You can use the direct selection tool to change details, such as colors, shapes, etc. on a illustrator photo.
If you use the direct selection tool on a illustrator photo, you can move parts and change the size directly.
You can change the color, style, and length of a stroke of a line and shape. You can also fill a shape with a color or/and texture.
You can use the direct selection tool to change the look of a line or shape.
The one to the left was saved as an illustrator., while the one to the right was saved as a png.