Hi Kunaal,

Thank you for your question,

The customisation for many of the Symphony MessageML format elements is quite restrictive when compared to other markup languages such as HTML.

You can take a look & review the 'Style Attributes' supported with MessageML:
https://docs.developers.symphony.com/building-bots-on-symphony/messages/overview-of-messageml/messageml-basic-format-tags/style-attributes

There might be some limitations on using specific Style Attributes in checkboxes and textboxes depending on how you are planning on using the style attributes with the MessageML.

If you use the following PresentationML Renderer Tool to test and trial out your MessageML syntax to validate whether it will be supported by the Symphony front-end renderer. If it does not work or render on this tool, then it is unlikely that it will work inside the Symphony chat.

PresentationML Renderer Tool: https://renderer-tool.app.symphony.com/

If you have any further questions or feedback - feel free to let us know.