Qua MIUI THEME With Tutorial

Tutorial

The First Method: Non-Root and Non-UBL
This method does not require root or unlocking the bootloader (UBL). All you need to do is use an app like "Chaome Theme Editor" or "Theme Swap (MyThemer)." These apps can be downloaded from the Play Store or found through a search engine. Just be sure to check out a tutorial video, like this one for guidance.

The Second Method: Root Access and Xposed Framework
This method is only compatible with MIUI 8 and earlier versions. To use it, you will need root access, which can typically be obtained by unlocking the smartphone's bootloader, especially for newer devices. Once you have root access, you will need to install the Xposed framework and make sure it is running. Then, you can install the appropriate module, such as For MIUI 8 and above version or For MIUI7 or below version on the Xposed framework.

The Third Method: Custom MIUI ROM
Many of the Android smartphones on the market today have locked bootloaders, which can limit access to the device. This is often done by the manufacturer to keep users on a specific version of the Android OS. However, with an unlocked bootloader, you will have unlimited access to your smartphone, allowing you to flash custom ROMs, kernels, and recoveries. To use this method, you will first need to unlock the bootloader and then install a modified MIUI ROM like miuiam, globerom, xiaomi.eu, or miuipro. Once you have the modified ROM installed, you can simply install themes as you would normally.

For additional methods or help, you can look for information on Google or on related forums. Choose the method that you think is the most effective, simplest, and safest for you.