Looks like Labels. You could create the same labels in ArcMap, and then publish to ArcGIS Online.
1. Here is my point layer.
2. Enabled colored text background.
3. Changed the placement properties to place the label on top of point.
4. Changed Point Symbology to NoColor (also unchecked "Use Outline" option)
5. Here is how my point layer looks now, after enabling Labeling.
Think Location