Hi Dharmishtha,
I apologize for the delay in response.
Can you please share the error which was received on your site? I have tried to replicate the issue with the latest version 4.4.8, I am able to activate the plugin without any errors reported in the debug.log file or on the screen.
You can as well try to follow the below steps on your site to debug the issue:
1. Deactivate all the plugins except WooCommerce and the WooCommerce Print Invoice & Delivery Note plugin.
2. Please check if the issue is fixed.
3. If yes, then you can start activating the plugins one by one and see which plugin is conflicting with our plugin.
4. If not, then can you please switch to the default WordPress theme or the WooCommerce StoreFront and see if it helps fix the issue.
Please let me know the result.
Regards,
Komal Maru