# Parameter Transformation
This article will show you how to perform API transformation on OpenAPIHub, for example, adding a header in an API request
You need to create an API before transforming an API, please follow ”Add API as Providers” to create an API.
# Where to Transform API?
You can transform API by editing an API, please refer to “Edit API as Providers” for how to edit an API.
# How to Create a Transformation?
- On the Transformations tab, select "Request" or "Response" then click Create .
- Fill in the form with all required information, including
- Parameter Type
- Action
- Key *Please be reminded not to use the ”List of Reserved Words for API Transformation”
- Type
- Value
- Click Save after you're done.