The Bitcoin address together with the private key of the Bitcoin wallet are the two main components when purchasing goods and services with this cryptocurrency. Bitcoin wallets can be of different types, forms and designs, and their goal is to protect your bitcoins and ensure secure storage of your funds. There are four main types of Bitcoin wallets:
Desktop Bitcoin wallet
Bitcoin-Qt is a desktop wallet installed in the original Bitcoin client. It allows users to establish a Bitcoin address for crypto-transactions and to preserve their private key. Other desktop wallets include Multibit (for Windows, Mac and Linux), Hive, Dark Wallet (emphasis on anonymity), etc.
Mobile Bitcoin wallet
A mobile wallet runs via an app on your cell phone allowing you to store private keys directly to mobile phone and instantaneously pay for various goods and services. Usually, the mobile wallets are not entirely Bitcoin clients, since they do not download the full version of the block chain that is constantly updating. Mobile clients often use simplified payment verification (SPV) that downloads only a part of the block chain. Most popular Android mobile wallets are created by Mycelium, Xapo and Blockchain.
Hardware Bitcoin wallets
Hardware wallets are only to the initial development stage and the variety of these devices is relatively low. The main representatives of the hardware wallets are Trezor and Mycelium.
Online Bitcoin wallets
Internet-based wallets, some of which can be linked to desktop and mobile wallets, store the private keys on the web. These wallets can be accessed from any device that is connected to the Internet. However, this type of storage implies entrusting your private keys to a third party, who theoretically can control your finances. CEX.IO is among the most frequently used online wallets. Not only you can safely store Bitcoins in a highly secure cryptocurrency cold storage, but also easily buy Bitcoins with a credit card by Visa or MasterCard.