Betfair is a betting exchange - an online marketplace for punters to bet against themselves on sporting and cultural events around the world. Customers bet against each other not against Betfair. There's no bookmaker telling you what odds you have to take.
On browser you can access the withdrawals page by selecting 'My Account' in the top right and then 'My Betfair Account': From the following page, a 'Withdraw Funds' button is present on the right-hand side. If you are able to withdraw this will be green. If you are not, this will be greyed out.
