You want to block incoming number? If so most current Smartphones have this feature built in so you would have to go through the phone menu to set it up.
However if you want to block your number from appearing on the other persons call display then again every smart & most dumb phones have this feature built in. You can also do it per call basics
To Block #31# followed by the number you are calling then press send.
To unblock *31# followed by the number you are calling then press send.
