These days, virtually all of the practices available to buy bitcoin also offer the option to sell. The exception is Bitcoin ATMs – some enable you to exchange Bitcoin for money, but not all. Coinatmradar will guide you through bitcoin ATMs in your region.
All exchanges enable you to both sell and purchase. What kind of exchange you choose to sell your bitcoin will rely on what sort of holder you are: tiny investor, institutional owner, or trader?
Some platforms like GDAX and Gemini are targeted more at big orders from institutional investors and traders.
Retail customers can sell bitcoin at exchanges such as Coinbase, Kraken, Bitstamp, Poloniex, etc. Each exchange has a distinct interface and some offer associated services such as safe storage. Some require confirmed identification for all trades, while others are more relaxed when tiny quantities are involved.
(Of course, don’t forget to declare any profit you make from selling to your tax authority!)
If you wish, you can exchange your bitcoin for other crypto-assets rather than cash. Some exchanges like ShapeShift concentrate on this service, enabling you to swap between bitcoin and ether, litecoin, XRP, dash, and several others.
Another option is direct sales. You can register on platforms such as LocalBitcoins, BitQuick, Bittylicious, and BitBargain as a vendor, and interested parties will contact you if they like your cost. Transactions generally take place via deposits or cables to your bank account, after which you are supposed to transfer the agreed quantity of bitcoin to the designated email.
Or, once they’ve set up a bitcoin wallet, you can sell it straight to friends and family. Send the bitcoin, collect the money or mobile payment, and have a celebratory drink together. (Note: it’s usually not a good idea to meet strangers to exchange bitcoin for the money with an individual. Be secure.)