Document document = new Document(FilePath + @"Example.docx");
var bookmarkcount = document.Bookmarks.Count;
if (bookmarkcount > 0)
{
//This means there are bookmarks in your document.
}
Document document = new Document(FilePath + @"Example.docx");
var bookmark = document.Bookmarks.FindByName("bookmark1");
if (bookmark == null)
{
//There is no bookmark named "bookmark1"
}
else
{
//The bookmark "bookmark1" exists in document
}