** Cause **
Click Configure> Project Default> Project Structure at the bottom right. Copy Path in Android SDK location The adb command resides in the "platform-tools" folder inside the "Sdk" folder. adb.exe is the adb command.
Open "System Properties". Click the "Environment Variables" button, click the variable Path in the system environment variables column, and click the "Edit" button. Click "New" and enter the Path to the platform-tools. Finish editing the environment variable name with "OK", finish the environment variable with "OK", and finish the system property with "OK".