Python comes with a number of built in packages such as "datetime" and "csv"

If you do:

import datetime
import csv

it will work with no issues.

Pandas is not a built-in python package. This means that you need to install it. Generally you can install it with:

pip install pandas

Read more on pandas installation at https://pandas.pydata.org/pandas-docs/stable/getting_started/install.html

Once pandas it is is installed your code it should work.

if you are starting to install external packages, you may want to read about virtualenv https://docs.python.org/3/library/venv.html