Putting in a new SIM card does not delete everything on an iPhone. The SIM card is primarily used for cellular connectivity and storing some user information, such as contacts and messages. When you insert a new SIM card into your iPhone, it will prompt you to activate the SIM card and may require you to enter the PIN code associated with the new SIM card.
However, it is important to note that changing the SIM card will not delete any data stored on the iPhone itself, such as photos, apps, or settings. These will remain intact unless you specifically choose to erase or reset your iPhone.
If you want to delete everything on your iPhone, you can do a factory reset or restore the device to its original settings. This can be done through iTunes or the iPhone’s Settings app. It is important to note that doing a factory reset will erase all data on your iPhone, so it is crucial to backup any important information before proceeding.
In my personal experience, I have had to change SIM cards on my iPhone multiple times when traveling to different countries. Each time, I would simply insert the new SIM card and go through the activation process. All my data and settings remained intact, and I could continue using my iPhone as usual.
To summarize, inserting a new SIM card into an iPhone does not delete any data on the device. The SIM card primarily handles cellular connectivity and stores some user information. If you want to delete everything on your iPhone, you can do a factory reset or restore the device to its original settings, but this is a separate process from changing the SIM card.