Is it legal to hide ip address or change ip address?

Your question is terribly open-ended, so wide that giving you an answer is pretty much just random, but ... Yes, it is legal to change your IP address and/or to hide your IP address (although "hiding" is not really practical; that's kind of like saying you're going to hide your phone number from the girl to whom you want to give it (sort of)).

(By the way, in the US, up until the past 30 years or so, the default status for pretty much any activity was "legal" unless specifically forbidden. We'd answer such questions as yours with, "It's a free country." Nowadays, the youngsters think they have to ask permission of their government to do anything. Sad.)

It's called security and it's perfectly legal to hide or change your network or computer IP number.

1 - You cant hide an IP.

2 - Changing ip is fine.

It's not *illegal* - because it's not possible. It's like giving someone a mailing address that's not yours, then expecting them to send you mail. Your IP address is the address to which the data you request gets sent. If you hide your IP address, or use one that's not yours, you're not on the internet.

you can't smart one