Hi Nantoine,
Thank you for your interest in Syncfusion Products.
You can find the documentation on Styles in the following links
http://help.syncfusion.com/ug_74/docio/WParagraphStyle.htmlhttp://help.syncfusion.com/ug_74/docio/AccessingStyles.htmlhttp://help.syncfusion.com/ug_74/docio/CharacterStyle.htmlPlease do find the sample from the below location which illustrates the same and provide more information if we misunderstood your requirements.
http://files.syncfusion.com/samples/DocIO.Web/SetStyles.zipPlease try this and let us know if you have any questions.
Regards,
Rajendran
