Can I use my TFSA as a trading account?

You can't use your TFSA as a trading account. The government deems the activity to be a business and then it is taxable. You can, however, use your TFSA for investing in stocks and bonds--the interest earned on those investments is tax-free as long as you don't withdraw those earnings.

For example, if you buy stocks in a company that pays dividends to its shareholders, the interest earned by those dividends remains tax-free.