diff --git a/tools/common/README.md b/tools/common/README.md
index 821b93d..444d200 100644
--- a/tools/common/README.md
+++ b/tools/common/README.md
@@ -6,8 +6,21 @@
 
 1. Place the files to be changed in a folder, e.g. **input**. 
 2. Create a folder in which the modified files will be stored, e.g. **output**.
-3. Call the file change_autor.py as shown below.
+3. Call the file *change_autor.py* as shown below.
 
 ```bash
 change_autor.py path_to_input_folder path_to_output_folder new_author_name
+```
+
+________________________
+**convert_directory.py** is a tool to convert all files in the directory to the specified format.
+
+## How to use
+
+1. Place the files to be changed in a folder, e.g. **input**. 
+2. Create a folder in which the converted files will be stored, e.g. **output**.
+3. Call the file *convert_directory.py* as shown below.
+
+```bash
+convert_directory.py path_to_builder_directory path_to_input_folder path_to_output_folder format_ext
 ```
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