There are a bunch of services for this, but in my experience 1) most customers prefer to just message you via Intercom/etc than go through a 'feature request' website, and 2) feature requests by themselves aren't very useful. When someone request a feature, you'll want to dive deeper into the problem they are trying to solve and then figure out yourself what the feature should look like.

So my recommendation would be to stick with email or however else customers currently reach out to you. Try to better understand their reasoning for requesting a feature. And if you absolutely must, keep track of these requests using a tool such as Trello, etc. But if you're just starting out it's probably fine to do it in your head as more common requests tend to resurface anyway.