diff --git a/www/apps/docs/content/modules/taxes/backend/create-tax-provider.md b/www/apps/docs/content/modules/taxes/backend/create-tax-provider.md
index ed7a78a954..23e723f187 100644
--- a/www/apps/docs/content/modules/taxes/backend/create-tax-provider.md
+++ b/www/apps/docs/content/modules/taxes/backend/create-tax-provider.md
@@ -127,18 +127,30 @@ The line item tax line object has the following properties:
 
 - `rate`: a number indicating the tax rate.
 - `name`: a string indicating the name of the tax rate.
-- `code`: an optional string indicating the tax code.
+- `code`: a string indicating the tax code.
 - `item_id`: the ID of the line item.
 - `metadata`: an optional object that can hold any necessary additional data to be added to the line item tax lines.
 
+:::note
+
+Tax lines for line item must have a unique `code` and `item_id` combination. Otherwise, the tax lines will be applied multiple times.
+
+:::
+
 The shipping method tax line object has the following properties:
 
 - `rate`: a number indicating the tax rate.
 - `name`: a string indicating the name of the tax rate.
-- `code`: an optional string indicating the tax code.
+- `code`: a string indicating the tax code.
 - `shipping_method_id`: the ID of the shipping method.
 - `metadata`: an optional object that can hold any necessary additional data to be added to the shipping method tax lines.
 
+:::note
+
+Tax lines for a shipping method must have a unique `code` and `shipping_method_id` combination. Otherwise, the tax lines will be applied multiple times.
+
+:::
+
 The returned array would be a combination of both the line item tax lines and shipping method tax lines.
 
 :::note