How to send this kind of messages?

Question

I want my bot to send messages in such bubbles, but I do not know the code.

Answer 1

Those "bubbles" are embeds, types of messages that can be sent only by bots. To send them, you'll need to use the RichEmbed class: you can create an instance of the class and then edit it with the methods you find in the docs. Here's an example with the image you sent:

let embed = new Discord.RichEmbed()
  .setColor([66, 134, 244])
  .setTitle("Zhontroly' si zprávy")
  .setDescription(":mailbox_with_mail: | Odeslal jsem ti do zpráv napovedu s příkazy!");

channel.send({embed});

Here's a more in-depth example, from "An Idiot's Guide"

const embed = new Discord.RichEmbed()
  .setTitle("This is your title, it can hold 256 characters")
  .setAuthor("Author Name", "https://i.imgur.com/lm8s41J.png")
  /*
   * Alternatively, use "#00AE86", [0, 174, 134] or an integer number.
   */
  .setColor(0x00AE86)
  .setDescription("This is the main body of text, it can hold 2048 characters.")
  .setFooter("This is the footer text, it can hold 2048 characters", "http://i.imgur.com/w1vhFSR.png")
  .setImage("http://i.imgur.com/yVpymuV.png")
  .setThumbnail("http://i.imgur.com/p2qNFag.png")
  /*
   * Takes a Date object, defaults to current date.
   */
  .setTimestamp()
  .setURL("https://discord.js.org/#/docs/main/indev/class/RichEmbed")
  .addField("This is a field title, it can hold 256 characters",
    "This is a field value, it can hold 1024 characters.")
  /*
   * Inline fields may not display as inline if the thumbnail and/or image is too big.
   */
  .addField("Inline Field", "They can also be inline.", true)
  /*
   * Blank field, useful to create some space.
   */
  .addBlankField(true)
  .addField("Inline Field 3", "You can have a maximum of 25 fields.", true);

  message.channel.send({embed});