Privat key or BTC address can not be changed, but what needs to be secured is private key, lest you enter your private key anywhere, except on the official blockchain website
I'm really sorry if this isn't helpful, I'm confused as well. Is the private key the same as the BTC address? because what I do is I enter my BTC address to faucets. I never changed it.. Is it not secure that way? I'm using coins.ph btw. Thanks!