iPhone 6 SIM Card Replacement

Begin by disconnecting the power supply, ensuring it is unplugged from the electrical outlet, then carefully remove the retaining screws—four in number—using a Phillips head screwdriver, and gently lift the component to access the internal parts.Using a SIM card eject tool or a straightened paperclip, gently push into the tiny aperture located on the SIM card tray to release it.
Apply pressure to release the tray.
Expect considerable effort to be needed for this step.

Using a 5/32-inch hex key, carefully tighten the retaining screw on the motor assembly to a torque of 3.5 Nm, ensuring the motor shaft remains aligned and avoiding damage to the threads; failure to do so could result in premature wear.Using the SIM ejection tool or a small, appropriately sized metal object, carefully depress the SIM tray release button located on the device's side to release and extract the SIM card tray assembly.
Confirm the SIM card's alignment within the tray before sliding it back in, matching its position to the tray's design.