@engahmed13
Welcome to HP Support Forums. 🙂 I understand that you have an HP laptop with Windows 10 installed and you would like to disable the touchpad. I read that when you double tap the upper left point on the touchpad it doesn't disable the touchpad. I appreciate the steps you have performed and have certainly done a good job. Let me assist you further.
-
In Windows, search for "mouse".
From the results list, click Mouse & touchpad settings.
-
Click Additional mouse options.
Figure: Additional mouse options

3. On the ClickPad tab, click and select " Disable internal device when external USB pointing device is attached).
Figure: ClickPad Settings

4. Click on Apply and then OK.
If the above steps do not work then you may try the below method:
1. Open the Mouse properties window again.
2. Click the Device Settings or the ClickPad Settings tab of Mouse Properties. If you have a Synaptics device, the tab includes the Synaptics icon
.
Figure: Device Settings

3. Select the desired touchpad under the Devices list, and then click either Enable to turn on the device.
4. To turn off TouchPad, click Disable.
Feel free to let me know the outcome. Cheers! 🙂