I suggest to provide a Free Trial of your software and for that, you can do some posting on social platforms. The genuine user can check your software and provide valuable feedback on your software and help to enhance it.
Thank you for good idea. I was thinking that accountants forum is appropriate for this, but maybe blog post and publshing it at Facebook/Linkedin can do better. Problem is, accounting software is not sexy, learning and checking takes time, switching costs are quite high, trust is difficult to establish. Not many accountatns easily want to discover what's new. How do I attract accountants to try and help? Is this just a numbers game - the more people read post the the more are chances somebody will try? Or maybe there is some specific social platform for accountants...
I would say your best bet is LinkedIn. There you should be able to narrow your search a little better to find a closed beta group for your design. I have set these kinds of things up in the past and it could be best to look at finance and accounting consultants to reach out too as they would be used to an entrepreneurial and changing environment. Be sure to look for a geographically reliable group and one that meets the qualifications of your desired end result (i.e. a testing group that you can rely on to end beta with a good sense of the market's realistic needs). LinkedIn Pro account for a month or two should help you narrow your search.
If you are targeting a particulars country, then it is better to target the Top 10 Forums/community for Accounting/Taxation/Finance having large numbers of subscribers and also try to tie with the Govt Department of Taxes who can promote the software among business as a Trial Software/ Free version as required.