Assuming that you mean you'd like to obtain physical cash, there are a two options that I can think of.
You could try trading with
LocalBitcoins. This is the most common method and involves either meeting up with someone in your local area in order to exchange your BTC for cash, or receiving cash in the mail if you can't find sellers in your area.
In my case, I use a BTC debit card to withdraw money into cash. In doing this, you can hold BTC in a third party account and spend fiat at merchants, selling your BTC at the point of use. You can also withdraw from ATMs (which I do on a fairly regular basis).
Debit cards often result in high fees and poor exchange rates, but they're very convenient and allow you to be flexible with the money, provided that you keep the bulk of your BTC in wallets that you control.
