Insert or delete a column in a paginated report (Report Builder)
Applies to: 
Microsoft Report Builder (SSRS)
Power BI Report Builder
Report Designer in SQL Server Data Tools
You can add or delete columns in a tablix data region in a paginated report. The tablix data region can be a table, a matrix, or a list. The following procedures do not apply to the chart and gauge data regions.
In a tablix data region, you can add columns that are associated with a group (inside a group) or that are not associated with a group (outside a group). A column that is inside a group repeats once per unique group value. For example, a column inside a group based the value in a data column that contains color names, repeats once per distinct color name. For nested groups, a column can be outside the child group but inside the parent group. In this case, the row repeats once for each unique value in the parent group.
Note
You can create and modify paginated report definition (.rdl) files in Microsoft Report Builder, Power BI Report Builder, and in Report Designer in SQL Server Data Tools.
To select a data region so that the row and column handles appear
In Design view, click the upper left corner of the tablix data region, so that column and row handles appear above and next to it.
For more information about data region areas, see Tables, Matrices, and Lists (Report Builder and SSRS).
To insert a column in a selected data region
Right-click a column handle where you want to insert a column, click Insert Column, and then click Left or Right.
-- or --
Right-click a cell in the data region where you want to insert a row, click Insert Column, and then click Left or Right.
To delete a column from a selected data region
Select the column or columns that you want to delete, right-click the handle for one of the columns you selected, and then click Delete Columns.
-- or --
Right-click a cell in the data region where you want to delete a column, and then click Delete Columns.
To insert a column in a group in a selected data region
Right-click a column group cell in the column group area of a tablix data region where you want to insert a column, click Insert Column, and then click Left - Outside Group, Left - Inside Group, Right - Inside Group, or Right - Outside Group.
A column is added either inside or outside the group represented by the column group cell you clicked on.
To delete a column from a group in a selected data region
- Right-click a column group cell in the column group area of a tablix data region where you want to delete a column, and then click Delete Columns.