Selling
To put it simply, selling works just like buying but in reverse. For mutual funds you just choose how much you would like to sell (in either units or dollars), and enter the order. For ETFs, you will enter a sell order (and your limit becomes the ask price). It will take 2 business days for your order to settle, so you won’t be able to withdraw cash right away, but you will be able to purchase other ETFs (because those purchases will also take 2 days to settle – though note that different countries can have different holidays if you’re buying and selling on different exchanges – you can always wait for the first trade to settle before placing another to be safe).
To then get your cash out and spend it is very straightforward with Tangerine or TD if you have an associated chequing account with them: just do an internal transfer, then pay bills, write a cheque, or withdraw as you ordinarily would from the chequing account. For Questrade, or the other options if you don't have an associated chequing account, you will need to set up an electronic funds transfer (the same three letters as ETF but note the order) to your chequing account at your bank.
Remember for regular cash or margin accounts (non-registered) that when you sell something you will have to report the capital gain (or loss) on your taxes that year.