There are a few different methods that may work to open a SIM card slot without a pin:
Use a paperclip:
Straighten out a paperclip, then insert the straight end into the small hole next to the SIM card slot. Push gently until you feel the slot release and then you can gently pull the tray out.
Use a safety pin or earring:
Straighten out a safety pin or earring and use the sharp end to gently poke the hole next to the SIM card slot. Push in until the tray releases.
Use a toothpick:
Use a toothpick to gently push the release button near the SIM card slot.
Take a small piece of tape and fold it in half so that the sticky side is facing out. Insert one end into the hole next to the SIM card slot and press it against the SIM card tray. Gently pull the tray out with the tape.
Remember, these methods may work for some devices but not for all, and using something sharp or abrasive to try to force open the tray can cause damage to your device. So be cautious while performing any of these methods. If all fails, it’s recommended to take it to a professional or the device manufacturer’s service center.