Where we can use Python:
We can use it everywhere. The most common important application areas are
1) For developing Desktop Applications
2) For developing web Applications
3) For developing database Applications
4) For Network Programming

5) For developing games
6) For Data Analysis Applications
7) For Machine Learning
8) For developing Artificial Intelligence Applications
9) For IoT

Note:

1.  Internally Google and Youtube use Python coding. 
2. NASA and Nework Stock Exchange Applications developed by Python. 
3. Top Software companies like Google, Microsoft, IBM, Yahoo using Python.