You can right click on any column header in Worksheet and then select Resize Columns...
Worksheet will then automatically resize all visible column widths to best fit their contents. This command can also be found in the View Tab, Columns, Resize Columns. After this function, you may need to manually adjust the Part Description width to your preference.
To manually resize any single column, position your cursor on the edge of the area of the column to resize until you see the cursor change to a double arrow. Click and hold the mouse button, drag to resize, then release the mouse button when you reach the desired width. Alternatively, you can also double left click the mouse when the double arrow appears instead of dragging to have the column width adjust automatically.