Trying to add cronjob results in ""LICENSE":0: bad minute"
You can't add a crontab entry by just running crontab &lt;entry details&gt;. In your case the shell expands the * with whatever filenames it finds in the current directory (which seems to be a file called LICENSE, replace crontab by echo to see what happened to the other *'s).

To add new entries to the crontab file run

export EDITOR=nano
crontab -e


add the line 

* * * * * /Users/username/Downloads/reddit-notifications-master/notifyer.sh


directly to the file and save it, then exit the editor again. You can verify that it got added by running crontab -l.

Some additional things to consider:


Run chmod +x /Users/username/Downloads/reddit-notifications-master/notifyer.sh to make sure the script is executable
Run type python3 in your shell and use the full path you get within notifyer.sh to avoid issues with python3 not being in PATH
If notifyer.sh is only used to launch the Python script you don't need the script at all, you can just add

* * * * * /path/to/python3 Users/yogesh/Downloads/reddit-notifications-master/reddit_notifications.py


to your Crontab instead.