You don’t have to register wallets. Depending what coin your are buying you can use a basic software wallet like metamask or trust, but these are hot wallets, connected to the internet. This is fine for small amounts for day to day use. For larger amounts you need to use a wallet that’s never seen the internet. So you need an offline machine that’s not going to ever be connected to the internet. Create your wallet address, then save the private key and public key (and seed phrase if that’s how the wallet was generated) If you are just holding coins then that’s litterally all you need, those keys saved safely written down is enough. There is no need for any software or hardware. Never keep any keys online and never keep large amounts in hot wallets.