That can be a hard question to answer on an online forum. It's going to depend on several things. What year, make and model is the car? Do you know the brand of alarm? Is it a basic alarm that only goes off if you open the door and maybe the trunk or is it interfaced with the electric door locks and trunk release? Was/is it a professional installation or a hack job?
It should not be that difficult to remove. Start by removing the negative cable from the car's battery. Then find the alarm's siren. Cut its wires and remove its mounting bracket screws. You can follow the siren wires and they will lead you to the location of the alarm module, or "brain" as they are sometimes called. It's probably under the driver's side of the dash, or maybe tucked in behind the driver's kick panel. Remove those panels and it is probably zip-tied in place. Cut it loose and it probably has 6 or 8, maybe more wires leading from it, depending on how complex the system is. Follow the wires and they will lead you to each part of the car the alarm is interfaced with. It is probably connected to true ignition 12 volts, constant 12 volts and a starter interrupt relay, all of which may be connected right at the ignition switch harness below the steering column. Cut the alarm's B+ and ignition wires, and tape up any exposed wire ends. If it has a starter interrupt, you may find the starter wire has been cut in two and a relay connected, cut the wires from the relay and splice the starter wire back together, then find the relay and remove it from the car. It's probably zip-tied somewhere near the steering column. Some alarms have a built-in on board starter kill relay. If so you will only have 2 wires, about 12 or 14 gauge going from the alarm module to the point where the installer cut the starter wire. Cut them loose and splice the starter wire back together.
Then you can disconnect the wire where the installer interfaced with the parking lights. Cut the wire and tape up any loose or exposed ends. You may have a trunk release or door lock interface to remove too. Same thing, follow the wires from the alarm to the point where it is connected to each circuit, cut it out and tape up the wire in the car.
You probably have a valet/override switch in there somewhere, they are easy to remove, it will either have a nut on the front of it or it may be a snap-in switch. There may also be an external shock sensor, if so it is probably zip-tied in place somewhere, probably on a large wire harness under the dash. There is a ground wire for the alarm, follow it to its connection point and cut it loose. Some alarm installers will wire the B+ voltage wire to a separate wire from the positive battery terminal and run it inside the car. You will have either that or the B+ connection at the ignition harness. In some cases it could be done at the fuse box, but unless it's an older Honda that's not very likely.
It should not be very difficult to remove the alarm. They really are all about the same but it depends on the type of car and the brand of alarm.
