Method 1
Click the first cell of the column to make it active, then move the cursor to the edge of the column, you will see a double arrow icon. Hold down the left mouse button and drag to adjust the width.
Method 2
Click the first cell of the column to make it active, then click "Edit" on the top menu bar, and the Edit submenu appears, as shown below. Click "Column Width +" or "Column Width -" to increase or decrease the width.
