Edit/Modify command

The HATCH command is used to draw hatching lines in a closed boundary region. The hatch pattern is identified by a pattern name.

The Offset command creates new object parallel to the original object at specified distance and direction.

The FILLET command is used to draw chamfering arcs connecting two lines of specified radius

The CHAMFER command is used to draw beveled lines connecting two lines at specified distance from the corner of two lines 

AutoCAD 2D commands

• DRAW COMMANDS

  Limit

As a first step for drawing area setup need to set limits on screen 

for that Limit command is used

¡The limits command allows to change the upper and lower limits of the drawing area. The lower limit is normally kept at 0, 0 and the value of the upper right corner depends upon the size of the figure to be drawn. The default size is 12x9 units. The size of the upper right corner should be slightly more than the size of the figure to be drawn

¡Command: LIMITS
¡Reset Model space limits:
¡Specify lower left corner or [ON/OFF] <0.000; 0.000>: 0, 0 (Enter)
¡Specify upper right corner <12.000, 9.000>: 297, 210 (Enter)

For more detail related to draw command you may concern a video given below that will help you to learn about draw commands 

Basic Information About CAD

CAD INFO

• What is CAD?

Almost most of peoples are thinking that CAD means AutoCAD, but but but think about what CAD is stand for CAD means "Computer Aided Design" define that CAD will help to create Design in computer  doesn't mean that in AutoCAD only there are many option for design like Solid Works, Pro-E, Fusion 360 and many more....

• Why we need this different software?

All the software has there own strength and different facility we are going to know that particular strength and weakness of software that will help you to select software for your project.