How to adjust the column's width
The width can be modified from the gradebook itself.
The width of the columns can be changed individually with a tap in the column's header or it can be done in bulk from Tools > Columns and Categories.
Change width and height by just dragging the circles next to each column
Change its width from the column properties (double tap on header)
To change the width in bulk, tap on Tools > Columns and Categories then Select the desired columns and Edit its width.