Change the Bluetooth device password from the Bluetooth settings of your operating system. While the exact procedure depends on the operating system that the device connects to, Bluetooth settings are usually under network settings. Most devices do not allow the user to change the password.
If using an Android device to pair with the Bluetooth device, tap the Settings icon on the home screen and choose Wireless & Networks from the list. Tap Bluetooth, and then tap the Bluetooth device with the password you want to change. Type a new password when prompted to do so, and tap OK.
On a Windows computer, click the Start button, then click Settings, and then click Devices. Navigate to the Bluetooth tab and click the device you want to pair with the computer. If the device allows you to change the password, you can enter a new one in the pairing wizard.
If using an iOS device, open the Settings application from the home screen, choose General from the list and tap Bluetooth. Choose the Bluetooth device and enter a new password.
Make sure both the Bluetooth device and the device you want to pair it with are discoverable. If the device does not allow you to change the Bluetooth password, there is no way to change it. In that case, you either need to use the password provided in the user manual, or one of the devices generates a random password that you must enter on the other device. For instance, when trying to pair one of Apple's wireless keyboards with a Mac, the computer gives you a random password that you must type on the keyboard.