To resize a column, move the mouse pointer between the columns as shown below. The mouse pointer will change and you can then drag the mouse left to shrink the column or right to enlarge the column. To adjust the row height, move the mouse pointer between the rows headers. The mouse pointer will change and you can then drag the mouse down to enlarge the row or up to shrink the row.
NOTE: To resize multiple columns at one time, select all the columns by clicking and dragging the mouse on the column headers. With the columns selected, resize one of the selected columns and all the selected columns will be sized the same. The same method can be used to resize multiple rows at one time.