On your Task List page, to the right of the column headings, click the drop-down ellipsis (...).
On the menu that appears, choose Gantt Chart.
The Gantt Chart View splits the content display and the Gantt chart with a slider. Move the slider to display the columns that you want to see.
In a Gantt Chart view, click the drop-down arrow next to any column heading.
On the menu that appears, click Configure Columns.
In the Configure Columns dialog box, you can perform any of the following actions:
Hide or display a column by clearing or selecting the check box next to the column name.
Change the column display order by selecting a column and clicking Move Up or Move Down.
Change the width of a column by modifying the Column Width value.
Click OK to save your changes.