Invoicing System - get users.

Hello, I just deployed a web page to show my invoicing system that i am going to launch next month. I have added a waitlist to see how many users are interested, but i am thinking now, of how to promote such system? How to get potential users that needs this system, or at least how to reach them to make them aware that this system is going to be in the market? One last thing, i am still thinking of the monthly subscription. I am between 15 - 30 euros per month without freemium features. Is it better to have free features and a more expensive subscription, or a cheaper subscription without free features.

This is the webpage for anyone that is interested to give me some feedback:
https://e-nvoicing.com/