You don't have to turn off your phone to switch SIM cards (but you probably should)

Swapping SIM cards is an infrequent task that requires careful execution, and while powering off the device is not strictly mandatory, it remains a recommended practice. Additionally, modern smartphones now integrate numerous built-in features that previously required expensive third-party subscriptions. Users are encouraged to explore these native capabilities before paying for external apps, as many essential tools are now included as standard components of the device's operating system to save costs.