Re: https://bitcoinvanitygen.com/

It is a known scam site, do not use it. For scam accusation threads, google 'bitcoinvanity scam bitcointalk'

so what site is legit one to make custom address? pls give

You should not use websites to create vanity addresses as that generally means they have the copy of private key of that address and are able to use the BTC in that address any time they want.
Create a vanity address yourself, https://bitcointalk.org/index.php?topic=25804.0

i can't understand Huh

too complicated for me Embarrassed

is there any trusted service that offer custom address?

Let me guess, you use online wallets too because running Bitcoin Core locally is too difficult ?

The only way to completely be sure the key is truly private is to generate it yourself. Don't ever trust services to create private keys for you.

It would be good for you to take the time to learn about this sort of stuff if you plan on being involved with Bitcoin long term.