http://ssd.iykpqm7jiradoeezzkhj7c4b33g4hbgfwelht2evxxeicbpjy44c7ead.onion/module/communicating-others
Some examples of services that do not offer end-to-end encryption by default include WeChat, Slack, Discord, Snapchat, and QQ. And then there are also some services, like Telegram, which only offer end-to-end encryption if you deliberately turn it on, while others, like iMessage, only offer end-to-end encryption when everyone in the conversation use a particular device (in the case of iMessage, everyone in the chat needs to be using an iPhone).