diff --git a/hathizip/__main__.py b/hathizip/__main__.py
index c4e0c43..0bc240a 100644
--- a/hathizip/__main__.py
+++ b/hathizip/__main__.py
@@ -5,7 +5,7 @@
 from hathizip import cli
 
 
-def main():
+def main() -> None:
     """Check if pytest arg is run else run main entry point."""
     if len(sys.argv) > 1 and sys.argv[1] == "--pytest":
         # pylint: disable=import-outside-toplevel
diff --git a/hathizip/cli.py b/hathizip/cli.py
index 9e84dfb..21c3940 100644
--- a/hathizip/cli.py
+++ b/hathizip/cli.py
@@ -4,17 +4,19 @@
 import os
 import shutil
 import sys
+from typing import Optional, List
 
 from hathizip import process, configure_logging
 from hathizip.utils import has_subdirs
 
+
 try:
     from importlib import metadata
 except ImportError:
     import importlib_metadata as metadata  # type: ignore
 
 
-def destination_path(path):
+def destination_path(path: str) -> str:
     """Validate the entry point for the cli args.
 
     Args:
@@ -85,7 +87,7 @@ def get_parser() -> argparse.ArgumentParser:
     return parser
 
 
-def main(argv=None):
+def main(argv: Optional[List[str]] = None) -> None:
     """Run main entry point for the program."""
     argv = argv or sys.argv[1:]
 
diff --git a/hathizip/configure_logging.py b/hathizip/configure_logging.py
index 0d5d29d..2611e56 100644
--- a/hathizip/configure_logging.py
+++ b/hathizip/configure_logging.py
@@ -2,9 +2,13 @@
 
 import logging
 import sys
+from typing import Optional
 
 
-def configure_logger(debug_mode=False, log_file=None) -> logging.Logger:
+def configure_logger(
+        debug_mode: bool = False,
+        log_file: Optional[str] = None
+) -> logging.Logger:
     """Configure logger.
 
     Useful for passing logging information
diff --git a/hathizip/process.py b/hathizip/process.py
index 12a4981..0dc6e8d 100644
--- a/hathizip/process.py
+++ b/hathizip/process.py
@@ -12,7 +12,7 @@
 
 
 # TODO: create get_files testing
-def get_files(path) -> typing.Iterator[PackageFile]:
+def get_files(path: str) -> typing.Iterator[PackageFile]:
     """Find files relative to a given path.
 
     Args:
@@ -33,7 +33,7 @@ def get_files(path) -> typing.Iterator[PackageFile]:
             )
 
 
-def compress_folder(path, dst):
+def compress_folder(path: str, dst: str) -> None:
     """Compress the contents of a path.
 
     Args:
@@ -66,7 +66,7 @@ def compress_folder(path, dst):
         logger.info("Generated {}".format(final_zip))
 
 
-def compress_folder_inplace(path, dst):
+def compress_folder_inplace(path: str, dst: str) -> None:
     """Compress the contents of a path without using a temp directory.
 
     Args: