This is difficult to answer because we can't link to things (see the rules to the right). I started off using publicly available channels, which is a convenient way to learn how it works. I just did a search for IPTV and in my search results I got a link to GitHub that provides you with information about how to use the public channels. You might like to try the same to start using it. If you want to get more content, the best way to find out about other IPTV services is to ask individuals you might have in your chat programs. For example, I have a friend on Steam that tells me about the services he uses. If you have the VLC media player this will help you a lot.

People do not like sharing their IPTV providers, and instead gatekeep them to "protect them". You're gonna have a tough time getting a good one, good luck.

I found my iptv provider by asking in the class restricted forum of one of the private trackers I use.

It isn’t the easiest thing, so many reviews are just self promotion. There are some forums and discords that are pretty reliable with good discussion but it’s mostly trial and error to find one that works well for you.