Syncfusion Dashboards. Cloud-based. The only BI solution you need for your business.
You can load the existing pdf file using PdfLoadedDocument and you can add the annotation at the specified page of the loaded document.
Refer the following code example to achieve the requirements as specified above:
You are using an outdated version of Internet Explorer that may not display all features of this and other websites. Upgrade to Internet Explorer 8 or newer for a better experience.