Both Apple and Android devices can use eSIMs, but you must confirm that your device is compatible with eSIM technology.
Apple (iOS) devices
Go to the Settings app → General → About → Model Number until you view an "AXXXX" combination. Most iPhones sold in mainland China, Hong Kong, or Macao do not currently support eSIMs.
Android devices
Go to the phone Settings → Connections → SIM Manager. Now if the option Add eSIM is available, your device supports eSIMs.
Google Pixel devices
Open the Settings app, search for Network & Internet, tap the plus sign (+) next to SIMs, and if you open the screen labeled "Connect to mobile network" and see "Download a SIM instead," then your device supports eSIMs.
Other Android devices
Dial *#06# and press the Call button. If you can view the eSIM unique identification number (EID), then your device supports eSIMs.