How to add HTML, CSS or Javascript?

Open the Block Library → Other and add the T123 block.

In the block’s content panel, add the HTML, CSS, and JavaScript code.

The code will run on the published page.

The block supports HTML, JavaScript (inside the <script> tag) and CSS (inside the <style> tag). Unfortunately, you cannot add your PHP code to the page.

Note that Tilda doesn't provide support for any issues related to the external code.