This applies to iPhones that uses nano sim card – i.e. 5, 5c, 6, 6 Plus, 6s, 6s Plus, se, 7, 7 Plus
Check out the video how to here https://youtu.be/ERJfPy8sF20
You will need a sim card removal tool which usually comes in the box with your iPhone and is inside the manual section; or you can use a paper clip, don’t use anything sharp as it can damage the interior of your phone. These days, nano sim is included in the same card as standard and micro sim, I got mine from Utility Warehouse. Punch out the smallest which is the nano sim.
1. Turn off your iPhone. You can leave it on if you wish, but I would recommend turning it off before you remove the old sim or insert a new sim card.
2. Locate the sim card tray on the right hand side of your iPhone, just under the power button.
3. Insert the sim card removal tool or paper clip into the sim slot hole, then press firmly until the sim tray slides out.
4. Take out the tray, remove your old sim (if there is one there).
5. Carefully align your new nano sim card, the metal circuit board side down, making sure the slanting edge aligns in the sim tray.
6. Re-insert and push the sim tray with your new sim card into the iPhone.
7. Turn on your iPhone which will detect your sim and phone signal.