If you are already a Yesware user, simply go to app.yesware.com/account/plan to see your current plan and to choose a new one.
Yesware offers three plans: Pro, Team and Enterprise. You can find costs and feature descriptions on your plan page as well as online here.
Please note that the only plan that has a monthly billing cycle option is our Pro plan. The Team and Enterprise plans must be paid upfront on an annual billing cycle.