Switching to Paid Account

• General
  • I have a trial account, how do I switch to a paid account?
  • How do I switch to a paid account using credit card payment?
  • What are the payment methods (billing methods) available to me?
  • What type of credit cards can I use?
  • How do I buy more user licenses?
  • How do I buy more storage?
  • I would like to purchase more than 50 user licenses. How do I do this?