There are two main approaches to filter and transform data based on header information in Power Query:

1. Filtering based on Header Values:

* Filter Rows: This is the most straightforward approach. You can filter the entire table based on specific values within the header row.
* Select the table you want to filter.
* Click "Filter Rows" under the "Home" tab.
* In the "Filter Rows" dialog box, choose the appropriate column (your header row) and enter the filtering criteria. You can use various operators like "equals," "contains," "starts with," etc.
* Click "OK" to apply the filter.

2. Transforming Data using Header Information:

* Conditional Columns: This method allows you to create new columns based on conditions defined using header information.
* Select the table you want to transform.
* Go to the "Add Column" tab.
* Click "Conditional Column."
* In the "Formula" bar, use a combination of header references and logical functions (IF, SWITCH) to define the transformation logic based on specific header values.
* Name your new column and click "OK."

Here are some additional techniques you can use:

* Text.Split: This function can be used to split the header text into separate components (e.g., splitting "Product ID" into "Product" and "ID") and use those components for further filtering or transformation.
* List.First/List.Last: If your headers contain multiple values separated by delimiters, these functions can extract the first or last value for further manipulation.
* Custom Columns: You can write custom M language code to perform complex transformations based on header information.

Remember:

* Power Query uses a formula language (M) for advanced transformations.
* You can find detailed information and examples for these functions and features in the official Microsoft documentation for Power Query M: [https://learn.microsoft.com/en-us/power-query/](https://learn.microsoft.com/en-us/power-query/)

By combining these methods, you can achieve powerful data filtering and transformation based on the information contained within your header row.