FIRST WAY:


Step 1: In our app, select Frontend Download option on the sidebar: 



Then:

  1. Select option for Order
  2. Edit everything as you wish
  3. Preview the buttons
  4. Scroll down and click Copy to copy the code



Step 2: In your Shopify admin page, click on Online Store -> Themes, then Actions -> Edit code:




Step 3: Look for customer/order.liquid in Templates, then paste the previous code at the bottom, and click Save:




Customers can now see the Download button(s) when they view orders from their Account page:



SECOND WAY:


You could also add the Download button on the order list page, like this:


Steps are as below:


Step 1: In our app, Go to Frontend Download page, and copy the link as in the picture:



Step 2: In your Shopify admin page, click on Online Store -> Themes, then Actions -> Edit code like the first way, and find the customer/account.liquid file:




Step 3: Find the <thead> label, and add the previous code right after the last <th>

<th><span class="table">Invoice</span></th>




Step 4: Find the <tbody> label (which should be right below <thead>, and add the below code after the last <td>

                    <td>

                      <span class="invoice">

                    <a target="_blank" href="https://api-pdf.vify.io/api/pdf-preview/invoice?shop_domain={{ shop.permanent_domain }}&order_id={{ order.id }}&locale=en">Download</a>

                      </span>

                  </td>


Click Save and finish.