Depending on who you are, you will have different access to channels.
In your head, you have some idea of which channels would work for reaching companies that would benefit from this software. Maybe you're imagining using your network for referrals, or maybe you see yourself signing up for LinkedIn Sales Navigator.
Either way, before committing to an idea, you should test these channels and see if you can get the results you expected.
You can do this a few different ways, but the simple version is to do the following:
If it's a community that you can post content to, write a blog post and see if you can get to the front page with your content. This is a good sign that you can reliably reach an interested audience in that channel
If it's cold outreach, you'll want to set low expectations, and then make sure you can hit at least those. For example, if I guess that ten out of 100 cold emails will be responded to, I need to at least check and make sure I'm right. If I end up getting 0 out of 100, I know that I need to not treat cold email as a viable first channel, and I'll need to find something else if I want to start on this idea.
PS. A good technique is to reach out and offer to interview your target customer for a market round-up post. People much prefer to be interviewed than to give up their time to strangers.
For channels that can't be tested in a short period of time (most notably SEO, but also PR, integrations, free software as a lead magnet), you'll want to speak with an expert or someone who you trust and has experience in that field. They'll have a much better idea than you do if you have realistic expectations.
If you're thinking that being on an App Store of a major store (Intercom, Hubspot, etc), be careful. It's not always the case that these stores will drive you sustainable traffic. You should still explore other channels, and I'd recommend not pursuing an idea unless you have a channel outside of the app store your app lives on.