There are countless language-exchanges online but I've decided to only highlight a couple--all of which are free. I've listed what I believe are the pros and cons of each one but in the end it's up to you. These sites are free so you can try them all out and simply stick with the one or two that you like most!
(All of these in this list are sites you can access from a computer. Many of them you can also access as an app.)
1. Coffeestrapwww.coffeestrap.com "A Better Language Exchange. Learn how to speak fluently by talking with people like you."
Pros: Very simple design, easy to get started, connects you to people without much work; easy to start talking to people.
Cons: Must wait for someone in your target language to get online; there's only one page (besides updating your account) and thus can be frustrating; once you accept someone's request, they'll remain in your conversation list, regardless of whether you want to keep talking to them or not.
2. Gospeakyhttps://www.gospeaky.com/ "Find and meet native speakers from all around the world."
Pros: You can select the times you're available to practice; live chats allow you to audio or video call someone, and add them as a "language buddy", there's a "translator bar" to help you; live chats only show you who is currently online; visually aesthetic and easy site to explore; you can schedule meetings with your buddies.
Cons: In live chats you must wait for a potential language-exchange partner to answer an instant message before you can call them; other than that, doesn't seem to have many cons.
Note: Will only show you live chats that are in your target language, if you want to find a live chat in a language other than the one you're learning, you'll have to add it to your target language list.
3. Howdoyou.dohowdoyou.do/ "Learn and practice foreign languages with native speakers from all over the world - for free."
Pros: After you chat with someone, you can recommend them again (so others can see how recommended they are); site shows if someone is online; you can use the search bar to find a chat with someone in your target language; can have multiple chats open at once (tabs at bottom let you easily switch between).
Cons: Search bar isn't that great--only shows you a couple of people that speak the language you type in, and doesn't say whether or not they're online, you're better bet is to just scroll down the 1:1 chats until you find what you're looking for; group chat seems messy.
4. Couchsurfingwww.couchsurfing.com "Couchsurfers share their homes, cities and lives in profound in meaningful ways, making travel anywhere in the world a truly social experience."
Pros: Lots of groups (easy to find language-exchanges); people from all over the world (likely to find exchange in your target language).
Cons: Activeness in groups is hit or miss; site is not made for language-exchange (simply a byproduct).
5. Coeffeeen.coeffee.com "The friendly language exchange community."
Pros: There are language games (like the old "password" game) that pairs you up with a random partner against two others (you and your partner have to try and guess a word before the other team by the clues you or your partner are giving--i.e. if you're trying to guess "star", you might say "bright thing in night sky"); the search for language-exchange partners shows who is online at the top, if you hover over them it'll tell you what languages they know / are learning, there's also a search bar at the top that can specify your search; can block people if necessary; glossary (dictionary) available during language-exchange chat.
Cons: Site seems focused on this language game rather than on language-exchange.
Note: You can also help other language learners by reviewing phrases for the "password" game.
If you google "language-exchange sites reviews" you'll find many longer (and potentially better) reviews. Figure out which site works best for you and stick with it! Finding a language-exchange partner can help boost self-confidence and make you more relaxed when speaking. ^^