If you find a website offering a "WinterBoard IPA" for a non-jailbroken iPhone, . These are often fakes or clickbait. True system-wide theming still requires a jailbreak.
WinterBoard IPA is a popular jailbreak tweak that allows users to customize the look and feel of their iPhone or iPad. The tweak is part of the Cydia ecosystem, a platform that offers a wide range of jailbreak apps and tweaks. WinterBoard IPA is designed to work with jailbroken devices, allowing users to personalize their device's interface with custom themes, icons, and other visual effects. winterboard ipa
WinterBoard supported:
Steps: