When you download that plugin you are suppose to get the following file:
change-wp-mail-from-details.zip
You don’t have to open this file. Do the following to install this plugin from that zip file:
1. Go to the “Add New” plugins screen in your WordPress admin area
2. Click the ‘”upload” tab
3. Browse for the plugin file (change-wp-mail-from-details.zip)
4. Click “Install Now” and then activate the plugin