Smartphone - Tagged Questions

• How do I turn on the "Okay Google" voice activation feature on my Android phone? I've tried looking in settings but can't find the right option to enable hands-free voice search.
• My phone's SD card is full and I'm getting storage warnings. What's the safest procedure to free up space—should I delete files directly format the card or transfer data to a computer first?
• My Android home screen is cluttered with apps I rarely use. Is there a way to hide specific app icons without uninstalling them perhaps using the settings or a third-party launcher?
• I've been searching everywhere online and in stores for the HK CC9 phone model but it seems to be completely out of stock or unavailable. What's the reason behind its scarcity—is it discontinued or limited to certain regions?
• With so many models which Xiaomi phone currently offers the best overall package in terms of camera performance and battery life for the price? I'm considering the Redmi Note series or a flagship.