How to convert JSON to rich HTML with relevant tags

I'm working with a charity who need their own specific CMS to post blogs. I have set up QuillJS which works well and output JSON.

How do I convert JSON data back to HTML with the relevant tags? I need the HTML tags to be shown too such as '<p>Hello</p>'. I can get the JSON data via php mysql but don't know how to show the tags.

For example how to I convert the following

JSON

{
   "time" : 1589493865899,
   "blocks" : [
       {
           "type" : "header",
           "data" : {
               "text" : "Editor.js",
               "level" : 2
           }
       },
       {
           "type" : "paragraph",
           "data" : {
               "text" : "Hey. Meet the new Editor. On this page you can see it in action — try to edit this text."
           }
       }
   ],
   "version" : "2.17.0"
}

HTML

<html>
<h2>EditorJS</h2>
<p>Hey. Meet the new Editor. On this page you can see it in action — try to edit this text.</p>
</html>

Many thanks in advance for any help!

Solution

Here's a complete solution. Each step is mentioned in the comments:

<?php
$jsonData = '{
   "time" : 1589493865899,
   "blocks" : [
       {
           "type" : "header",
           "data" : {
               "text" : "Editor.js",
               "level" : 2
           }
       },
       {
           "type" : "paragraph",
           "data" : {
               "text" : "Hey. Meet the new Editor. On this page you can see it in action — try to edit this text."
           }
       }
   ],
   "version" : "2.17.0"
}';

//decode the JSON
$data = json_decode($jsonData);

//loop through the blocks
foreach ($data->blocks as $block)
{
    $start = "";
    $end = "";

    //detect the element type and set the HTML tag string
    switch ($block->type)
    {
        case "header":
            $start = "<h2>";
            $end = "</h2>";
            break;
        case "paragraph":
            $start = "<p>";
            $end = "</p>";
            break;
    }

    //output the final HTML for that block
    echo $start.$block->data->text.$end;
}

Demo: http://sandbox.onlinephpfunctions.com/code/ab862de1113d8744bc2d9463f7a7df2496491110