How to Add Bullets in PowerPoint

Have you tried BulletFormat.Character ?

Returns or sets the Unicode character value used for bullets in the specified text. read/write.

int Character { get; set; }

○If you want to represent unicode9675 with a white circle icon , you can cast the number to char as shown in this example or the concept code below.

char myCharacter= (char) 9675; // white circle unicode
textRange.Paragraphs(i).ParagraphFormat.Bullet.Character = myCharacter;

complete example

Since it doesn't work on your end, I created an example that does the job. Let me know if you have any other questions.

// Create the Presentation File
Application pptApplication = new Application();
Presentation pptPresentation = pptApplication.Presentations.Add(MsoTriState.msoTrue);
CustomLayout customLayout = pptPresentation.SlideMaster.CustomLayouts[PpSlideLayout.ppLayoutText];

// Create new Slide
var slides = pptPresentation.Slides;
var slide = slides.AddSlide(1, customLayout);

// Add title
slide.Shapes[1].TextFrame.TextRange.Text = "Title of slide.com";

// Add items to list
var bulletedList = slide.Shapes[2]; // Bulleted point shape
var listTextRange = bulletedList.TextFrame.TextRange;
listTextRange.Text = "Content goes here\nYou can add text\nItem 3";

// Change the bullet character
var format = listTextRange.Paragraphs().ParagraphFormat;
format.Bullet.Character = (char)9675;

pptPresentation.SaveAs(@"c:\temp\fppt.pptx", PpSaveAsFileType.ppSaveAsDefault, MsoTriState.msoTrue);
pptPresentation.Close();
pptApplication.Quit();