How to disable security system with starter interrupt

typically with an aftermarket device, the starter wire is interrupted under the column, close to the key switch.

follow the wiring from the keypad.

You will see that the starter wire is cut/separated, and the cut ends will be attached to a relay (or relay harness).

Re-attach as they would have been factory (solder & tape, or yellow butt connector), and remove keypad and all aftermarket wiring associated .