Using a simple program as example, the argparse library prints the following text:

usage: app.py [-h]

options:
  -h, --help  show this help message and exit

However, for more formality, it would be nice to print something like this:

Usage: app.py [-h]

Options:
  -h, --help  Show this help message and exit.

Notice the sentences start as capital letters and the helper string finishes with dot.

I would like to work on it as my first contribution to the python repository. Can you please assign this to me?

I don't think argparse should do such formatting. You can give it the help text in this format if that's what you want printed, and you can implement your own formatter: https://docs.python.org/3/library/argparse.html#formatter-class

I agree with @iritkatriel. Also, such a change to argparse would be too disruptive. So, I'm going to close this.