Adjust the double-click speed
Double-clicking only happens when you press the mouse button twice quickly enough. If the second press is too long after the first, you'll just get two separate clicks, not a double click. If you have difficulty pressing the mouse button quickly, you should increase the timeout.
Type "Settings" into the global search bar on your desktop. Click on the resulting Settings icon, or press Enter, to open.
Click on Mouse & Touchpad.
Under General, adjust the Double-click slider to a value you find comfortable.
Click the Test Your Settings button to test. A single click in the window will highlight the outer circle. A double-click will highlight the inside circle.
If your mouse double-clicks when you want it to single-click even though you have increased the double-click timeout, your mouse may be faulty. Try plugging a different mouse into your computer and see if that works properly. Alternatively, plug your mouse into a different computer and see if it still has the same problem.
This setting will affect both your mouse and touchpad, as well as any other pointing device.