Swati A.

A person who is good at drawing is called an artist.

But we can see the type of work and in a more specified manner call them with different names, like

a person who skeches as a sketch Artist

A person who is good at making cartoons as cartoonist

The one good at caricature a caricaturist

We can call a person good at drawing an illustrator or even as a Drawer.

Drawer is not used commonly, but it is a dictionary word for an artist.

Excel is one of the tools that is most widely used by people all over the world, As others have said, it is a very vast topic, but the basics can be learnt in 10-15 hours. And there are many additions to it, like VBA/Macros.. which will take an additional 20+ hours.
There is so much in that that if you do not practice it along with your classes it will be there just in the notes. Practicing it is very important. Fess can be variable according to the course and tutor. 

You apply your skills in various fields, you can choos one which interests you.
1. Graphic desiging

2. Fashion Designing

3.Professional Artist

4. Art Teacher

5. Animator

6. Curator

7.Textile designer

8. Illustrator

and many more you can explore the world of design with drawing skills

You can follow few tips to imporve drawing

1. Keep a sketch book handy, so that you can keep drawing everynow and then

2. Draw ordinary things to improve speed

3. Draw circles and squares which improves proportion

4. Try different colour schemes, to see which colours look better together. 

5. Think imagine and put your thoughts on paper

6. Should be able to recognise the edges.

7. Challenge yourself

It depends on your talent and your passion. The time and dedication you give to art. When it is from your heart you can be good in a year. 

If it is done only as a course, a study for making a living , then it depends on your concentration and dedication for your aim.

Just follow your heart when you learn something and art is a talent which flows out from the heart.