Use `open("filename.txt", "r")`

Read the entire file with `file.read()`

Read one line with `file.readline()`

Read all lines with `file.readlines()`

Iterate through the file with `for line in file:`

Use `with open("filename.txt", "r") as file:` to automatically close the file

Specify encoding if needed, such as `open("filename.txt", "r", encoding="utf-8")`

Close the file manually with `file.close()` if not using `with`