mjhjmtu

I read multiple articles refering the login shell and non-login shell,

still, I am very confused.
Difference between Login Shell and Non-Login Shell? - Unix & Linux Stack Exchange
The UNIX School: Login shell or a non-login shell?

Put it simple,

the shell I start from my own computer after I power on it,

Isn't it a login shell or non-login shell?

 $ echo $SHELL
 /bin/bash
 $ echo $0
 -bash

Additionally, Could you please help to determine taht the shell called from a program is login shell or not?

 import subprocess
 subprocess.run('ls -l', shell=True)

As noted in this answer:

prompt> echo $0
-bash # "-" is the first character. Therefore, this is a login shell.

So your first example shows a login shell.

As also noted in the same answer,

Information can be found in man bash (search for Invocation). Here
is an excerpt:

A login shell is one whose first character of argument zero is a -, or
one started with the --login option.

And from the Python docs:

... Popen does the equivalent of:

Popen(['/bin/sh', '-c', args[0], args[1], ...])

Since the only option given is -c, it's not a login shell.