Assuming that by M1 you mean a Mifare Classic 1k card, you should be able to use either the xM1 implant, or a flexM1. The xM1 is a small glass implant, preloaded into a syringe. It’s much easier to install (can be done by most piercers with some guidance), but the read range isn’t as good, and has issues being read by many door locks.
The flexM1 has much better read range, but it’s larger, and requires more expertise for install. It’s a flat flex-type implant. It’s either installed with an included 4 gauge piercing needle (stick needle in to a certain depth to make the pocket, then slip the implant in), or it can be installed using a scalpel and a dermal elevator.
If you haven’t found an installer in your area, you can look here:
It’s not a perfect map, but it should give you a starting point. Red pins should be able to install a flexM1 or an xM1, while a blue pin can likely just install an xM1.
What’s your model of door lock? You can check here, and see if it’s compatible with an xM1 or a flexM1.
If it’s not listed, it just hasn’t been tested by a forum member.
If you have any more questions, feel free to ask away.