`open(file, mode='r', buffering=-1, encoding=None, errors=None, newline=None, closefd=True, opener=None)`

Opens a file and returns a file object representing it.

file - a path-like object representing a path to the filesystem.
mode (optional) — mode in which the file is opened. If not specified, the default is 'r' (open for reading in text mode).
buffering (optional) — sets the buffering policy.
encoding (optional) — encoding format.
errors (optional) — string indicating how to handle encoding/decoding errors.
newline (optional) — newline mode (available values: None, '', '\n', '\r', and '\r\n').
closefd (optional) — must be True (default); otherwise, an exception is raised.
opener (optional) — custom opener; must return an open file descriptor.

Available file modes:

Mode	Description
`'r'`	Open for reading. (default)
`'w'`	Open for writing. Creates a new file if it does not exist or truncates the file if it exists.
`'x'`	Open for exclusive creation. Fails if the file already exists.
`'a'`	Open for appending to the end of the file without truncating it. Creates a new file if it does not exist.
`'t'`	Open in text mode. (default)
`'b'`	Open in binary mode.
`'+'`	Open for updating (reading and writing).

open() returns a file object that can be used to read, write, and modify the file.
If the file is not found, a FileNotFoundError exception is raised.

# Open the file test.txt in the current directory
f = open("test.txt")

# Specify the full path
f = open("C:/Python/README.txt")