To create a custom column, we need to follow some steps:
- First, we need to Launch Power BI Desktop and load some data.
- Once you launch Power BI Desktop then, from the Home tab on the ribbon, select Edit Queries, and then select Edit Queries from the menu.
- Then, from the Add Column tab on the ribbon, select Custom Column.
- Once you select Custom Column, then you will get to see a list of columns and in the Available columns list on the right.
- You can see New column name box. You can rename this column.
- In the Custom column formula box. You create these queries by building the formula on which your new custom column is defined.
To create formulas for your custom column:
- Select a column from the Available columns list on the right, and then select Insert below the list to add them to the custom column formula.
- As you enter the formula and build your column, note the indicator in the bottom of the Add Custom Column window.
- Select OK.
*Power BI Desktop adds your custom column to the model, and adds the Added Custom step to your query's Applied Steps list in Query Settings.
For more information you can follow this docs,