discord.js who sent the message code example

Example 1: how to send a message discord.js

message.reply("message here");
message.channel.send("message here");

Example 2: discord js message

client.on("message", message => {
    if (message.content.toLowerCase() === 'Hello') {
        message.channel.send("**Hey! What's Up?**")
    }
})
// This Will Print "Hey! What's Up?" When Someone Says "Hello" //