This app did what I needed and is very simple to use, and FREE. I created an invoice template and added this link to my Shopify order confirmation email, so as not to send yet another email to the customer. There were a few things that did not look right on the invoice, but the support was able to fix them within a day. I particularly like that I can send invoices in different languages to different customers.
Two things that would make this app better:
1) Make it clearer that you should TURN OFF email automation if you want to add the code to a Shopify email, instead of sending an extra email. That was very confusing to me, and took about 5 emails back and forth with the support team to clarify.
2) Create a packing slip template that does not include prices, similar to Shopify's packing slip template. A lot of our orders are gifts, so I do not want the recipient to see the price paid. For this reason, I will continue to use Shopify packing slips instead of yours.

Amazing service, app does just what it says it does. they can customize fields, layout, color, etc. Very great team, good and easy to deal with! thank you

The app is amazing to start up our business when it comes to printing invoices, packing slips etc. It's super customer friendly. On the support side: The team reacts extreme quickly to any requests and are always there to help on any requests. Top app

Great application and the most important thing is their support, very responsive & do the job. I sent them two cases & they solve it within two hours.

Super application, principalement lorsque l'on débute en dropshipping et hotline au top qui a traité l'ensemble de mes demandes. Je conseille vivement

Great app and easy to use. I had a few changes in the layout that I couldn't figure out, but customer support responded really quickly.

It's a great App! Easy to use, has a high level of customization and it's free! Thank you very much AVADA!

This is a fantastic app to help me with my packing slips and invoices. The customer service is amazing and this team goes above and beyond to ensure your happiness! Cannot recommend enough.

This app is very useful for our company and the customer support is amazingly fast and effective. Highly recommended.

I used this to create and email pdf invoice. awesome. I might buy the pro version very soon. I give a five star