You can install wordpress plugin in several ways . You can follow any of these steps :

Before installing , You need to have install & activate WooCommerce plugin.

Free Version

Automatic Installation

1. Navigate to the WordPress Dashboard > Plugins > Add New
2. Search for PDF Invoices & Packing Slips.
3. Click on Install and then Activate button.

Manual Installation

1. Download plugin from wp.org and unzip it.
2. Upload the entire folder to the /wp-content/plugins/ directory.
3. Visit Plugins.
4. Activate the PDF Invoices & Packing Slips plugin.

Premium Version

Before installing , You need to have install & activate WooCommerce and Free version of this plugin.

1. At first download the Plugin files from our website.
2. Now, Plugins Installations steps are similar as usual other's wordpress plugins.
3. After intalling Subscription for WooCommerce & Subscription Pro plugin. You need to insert License Key for upcoming pro plugin update.
4. Copy License key from our website & insert it.