Hi Jaish,
Thank you for using Syncfusion products.
Essential PDF allows you to add different cell styles to a cell in the PdfGrid by using our PDF library. We can customize the style of the complete grid cell from this approach. If you are using PdfHTMLTextElement, it supports rendering a style of each text inside the cell in a PDF document. This can be done by using the PdfHTMLTextElement class. The PdfHTMLTextElement class provides support for a basic set of HTML tags, to render HTML format text in the PDF document.
Please refer to the below link for more information,
You can use any of these approaches which suit your requirement. Please let us know if you need any further assistance with this.
Regards,
Gowthamraj K