my question is about like a online service that creates cold storage addresses
like a user press a button and a cold storage address is created on which he can sent its bitcoin and recover all the security stuff (private key ie)
If the service is online that creates the address or the address shows up the encryption key must be offline and must be held on an encrypted media device. I'm not really sure how this would be a good solution if this is what you're looking to do. Most cold storage is going to be either a paper wallet or USB drive and there's a handful of wallet applications out there that don't require you to be online to generate your address. (See Bitcoin Core)