How to display a label having text with line breaks?

There is no way of adding HTML tags in a <textarea> tag, so formatting with css for example or using <br> tags is not going to work.

Now, <textarea rows="4" cols="20">, is let's say the best you can do: you define the minimum rows to be show as "4" and the minimum amount of characters per row: "20".

The best method though is using <div contenteditable="true"></div> in which you can use tags like <br> and also css styling.

Give the label white-space: pre-wrap and it will break line as the text area does

textarea {
  height: 70px;
}
label {
  white-space: pre-wrap;
}

<textarea>
  First day
1-one apple.
2-one orange.
3-two cups of milk.
</textarea>

<br><br>

<label>
  First day
1-one apple.
2-one orange.
3-two cups of milk.
</label>

Besides the white-space property combined with a new line character (e.g. \n), the HTML way to break line is using <br>, add here is a small sample how they work and differ.

Note, even space's are preserved using e.g. white-space: pre, as seen in the "inline" code sample

var sample_script = document.querySelector('.sample.script');

var name = "One Two Three";
var name1 = name.replace(/ /g, '\n');
var name2 = name.replace(/ /g, '<br>');

sample_script.innerHTML += name1;
sample_script.innerHTML += "<br><br>";
sample_script.innerHTML += name2;

div.pre {
  white-space: pre;
}


/*  styling for this demo  */
body {display: flex;}
.sample {flex: 1; margin: 0 20px;}

<div class="sample inline">

  Inline
  <hr>
  <div>
    One
    Two
    Three
  </div>

  <div class="pre">
    One
    Two
    Three
  </div>
</div>

<div class="sample script">
  Script
  <hr>

</div>