You can't.
The reason is that the OPPO phone and the Apple Watch need different charging interfaces, which is not compatible.
The OPPO phone uses a USB-C interface, while the Apple Watch uses a dedicated magnetic charger.
Therefore, the OPPO phone cannot charge the Apple Watch directly. It should be noted that charging an Apple Watch with an unofficial or non-compliant charger poses potential risks to battery life and safety in use.
Therefore, it is recommended to follow the official guidelines and use the official charger for charging. In addition, there are also mobile charging banks specially designed for Apple Watch on the market, and users can choose to purchase these mobile charging banks for charging. These power banks are also designed in accordance with official specifications and are able to provide a stable power supply for the Apple Watch, while balancing mobility and portability.
OPPO is a smartphone manufacturer that usually offers phone chargers to charge phones. The Apple Watch uses its own battery and charger, so you need to use Apple's official charger to charge the watch. If you use the wrong charger or cable to charge, it may cause the watch to charge slowly or have other problems. It is recommended to always use the charger and cable provided by Apple to charge the Apple Watch.
No, the Apple Watch doesn't work with Android phones. The Apple Watch can only be paired with iphones running an iSO 8.2 or higher version of the iPhone 5.