How to solve HTML tags when adding to my page

Server Error in '/' Application. A potentially dangerous Request.Form value was detected from the client (ctl00$ContentPlaceHolder1$txtWeDoBody="... at work. <br /> You don’t hav..."). Description: Request Validation has detected a potentially dangerous client input value, and processing of the request has been aborted. This value may indicate an attempt to compromise the security of your application, such as a cross-site scripting attack. To allow pages to override application request validation settings, set the requestValidationMode attribute in the httpRuntime configuration section to requestValidationMode="2.0". ...