Is it possible to change a honda 5 speed car into a 6 speed car? If so what would you need to do?

Is it possible to change a honda 5 speed car into a 6 speed car? If so what would you need to do? - 1

If should be but the cost would be far greater than trading it for a 6 speed. Why do you want a six spend? What is the need?

Yes you can, but it depends on what engine your trying to mate the six speed too.
If you have a K20/K24 5speed or auto then yes. You would need 6spd tranny, 6spd shift box, 6spd shifter linkage, ebrake cable and other misc things.
Check out honda-tech.com for a more in depth list of this you need to complete your swap.