Your SIM card holds vital information suchas your cell phone number, your contact information and any text messages that you have saved to the phone. Removing and installing a SIM card on most phones is a rather simple process. Doing so on your iPhone, however, can be a little more difficult if you're not sure where the SIM card is located. Once you know where the SIM card is on your iPhone, you can easily remove the card.
Unfold the paper clip (if you're using a paper clip) so that it is straight.
Flip your iPhone so you're looking at the very bottom of the phone.
Find the small hole located on the bottom of the phone. This hole will be right next to the hole for your headphones.
Insert the paper clip or tack into the hole. The tack or clip should only go in about a centimetre or so.
Wiggle the clip or tack as you push it into the hole. Eventually the container holding the SIM card will become loose. Keep the clip or tack in the hole and gently begin to pull the container out. Do this until you can grab onto the container with your fingers.
Remove the container from the iPhone by pulling it out of the iPhone. Flip the container upside down to remove the SIM card from the container.
Place your SIM card into the container. Be sure to place the card into the container in the same that the original card was in the container.
Insert the container back into the iPhone. Push it into the open slot until you hear a "click." Wait a couple of seconds. The iPhone should then recognise the SIM card.
If there was no SIM card in the container, simply place your SIM card into the container right side up. In other words, the serial number on the card (located on the right side of the SIM card) should be right side up. Then, insert the SIM card with the front side of the card facing the back side of the iPhone.