If your crypto is on an exchange then it depends on the exchange, but you will no doubt pay fees to take it out and store it yourself.
Storing it on a hard drive is easy. You create a wallet and then transfer your crypto to that new wallet. (paying whatever fee to the exchange) The important thing is that the wallet will have the new key you require to spend it.
Is it possible to transfer current owned crypto into monero without paying transfer fees?
and how do you store it on a hard drive if you use an app?
If your crypto is on an exchange then it depends on the exchange, but you will no doubt pay fees to take it out and store it yourself.
Storing it on a hard drive is easy. You create a wallet and then transfer your crypto to that new wallet. (paying whatever fee to the exchange) The important thing is that the wallet will have the new key you require to spend it.
Coinbase and Robinhood don't let you transfer crypto in or out. You have to sell and then re-acquire through a private transaction.
I withdraw my crypto from coinbase pro often