Open Command Prompt(CMD) and use the below command. Replace the <chrome extension folder location> with actual location of the chrome extension folder within which the manifest.json file is located.
"C:\Program Files (x86)\Google\Chrome\Application\chrome.exe" --pack-extension=<chrome extension folder location>
"C:\Program Files (x86)\Google\Chrome\Application\chrome.exe" --pack-extension=C:\chrome_extension
Note: If your Chrome Browser is installed in a different folder, please use that path for "chrome.exe"
Use the below command in Terminal:
/Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome --pack-extension=./chrome_extension
Note: The above command will work for Linux as well with the respective folder for chrome binary.