Selfie sticks uses the volume button control to tell the phone to take pictures. So the phone should be able to take pictures with the volume buttons even without a selfie stick. This applies to any phone. If the phone is not taking pictures with the volume buttons, configure the phone’s camera settings.
Video: How to fix Selfie Sticks not working with Mi Redmi Android Phones?
If you are not able to use your Selfie Stick with Mi Redmi Android Phones, then check out the video how to fix it. It works, but there are a few places you need to change settings.