> For the complete documentation index, see [llms.txt](https://docs.getmesa.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.getmesa.com/tools/transform.md).
# Transform
The **Transform** tool converts the payload sent from the previous step into a form that the next step expects. Of the three different types of Transforms, the Transform Mapping is the most common. If you need fine-tuned logic, you can customize the script for every Transform.
## Transform Mapping
The Transform Mapping is by far the most common type of transform. The **Key** column represents the payload key that the next step will receive. The **Value** column represents the the value that the key will have. The value can be text (like `VIP` or `20.99`), or a [variable](/workflow-builder/fields/variables.md) that will be replaced by the corresponding value from the payload during execution.
When you click on the [Variables](/workflow-builder/fields/variables.md) icon \[<>] next to the value, a menu will appear with suggested variables (e.g. [Loop variables](https://github.com/shoppad/mesa-docs-gitbook/blob/master/tools/broken-reference/README.md)) based on the previous and next steps in the workflow. [It supports liquid-style variables](/workflow-builder/fields/liquid-templating.md) like `{{source.order_name}}`
In the example below, the Transform Mapping maps order data to the columns expected by the Google Sheets Write Sheet step.
## Transform Editor
The Editor Transform lets you create a JSON, HTML, or text payload. It supports liquid-style variables like `{{source.order_name}}`
## Transform Script
The Script Transform allows fine-tuned logic in a JavaScript script. Enter a human-readable description of what the script is doing, and then click **Edit Code** to start writing your JavaScript.
Read our technical documentation for more details about writing scripts: [Scripts](https://docs.getmesa.com/for-developers/admin-api#scripts) and [Script Specification](https://docs.getmesa.com/tools/custom-code/script-specification).