You can enable creating and sending of invoices in the language your customer used while shopping in your store by adding a unique code snippet to the cart file in your theme.
Step 1: In your Shopify Admin, go to the Online Store → Themes page.
Step 2: Click the Actions button, and then click Edit code.
Step 3: Select cart.liquid in the left sidebar. You might use the upper search bar for a faster search.
Step 4: Insert the following code snippet before the
Step 5: Click on the 'Save' button to save the change.