Is it possible to use custom fonts in ArcGIS Online Map Viewer Classic pop-ups?

Yes, it is possible to use custom fonts in ArcGIS Online Map Viewer Classic pop-ups. By default, there are six font options available for custom attribute configuration: Arial, Courier New, Garamond, Tahoma, Times New Roman, and Verdana.

The following steps describe how to use custom fonts in ArcGIS Online Map Viewer Classic pop-ups:

1. Log in to ArcGIS Online, and navigate to the web map.
2. In the Contents pane, navigate to the feature layer, click the More Options ellipsis icon, and select Configure Pop-up.

3. In the Configure Pop-up pane, click the Display drop-down list, and select A custom attribute display. Click CONFIGURE.

4. In the Custom Attribute Display window, type the desired text, and click the View HTML Source icon to view the HTML codes. In this example, the default font is Tahoma.

5. Change the default font with a desired custom font such as Brush Script MT in the source code.

Note:
The following steps may not be applicable to all custom fonts.

6. Click the View HTML Source icon to view texts with the specified custom font, and click OK to close the window.

7. In the Configure Pop-up pane, click OK to save the modifications.

The image below shows the text in the Brush Script MT font in an ArcGIS Online Map Viewer Classic pop-up.