The application is available for purchasing from the official website. There are 3 versions that you can buy: Standard, Business, and Enterprise. If you have a small firm, Business is the way because Enterprise is for large companies, therefore it will cost you a little more, but you can decide for yourself using the link below.
Buy page for SmartDraw: https://www.smartdraw.com/buy/
Note: Before buying, read all the text under the price table.