You can buy XRP using fiat (like US dollars or British pounds) or bitcoin.
XRP wallets operate similarly to other cryptocurrency wallets. Hardware wallets (like Ledger Nano S) and paper wallets are the best wallets for long-term holding of the coin. There is also a desktop wallet from Rippex for Mac, Linux, and Windows. There are no reliable mobile wallets for XRP at the moment. The security phrase for finding the wallet if you lose your primary device is important, and should be kept in a safe place.