Select the column you want to move
Move the cursor to the border of the selected column until it becomes a four-sided arrow
Hold down Shift
Drag the column to the new position
Release the mouse button, then release Shift
To swap two columns, move the first column to the second column’s position
Move the second column into the first column’s original position
Use Cut and Insert Cut Cells if you prefer:
Select the column
Press Ctrl+X
Right-click the destination column header
Choose Insert Cut Cells
Repeat for the other column if needed
To swap multiple columns, cut and insert each column in the desired order