Frequently asked question
In ArcGIS Pro, symbols or style items must be added to style files individually. This can be done by adding new styles or by clicking a symbol in the Contents pane or the Symbology pane to open the Format Symbol pane, and from the menu at the top-ight, click Save Symbol to Style. Refer to ArcGIS Pro: Save symbols and style items in styles for more information.
Equivalent ArcMap functionality does not exist in ArcGIS Pro, but there is an open enhancement. Refer to Esri Community: ArcGIS Pro "Export Map Styles" for bulk saving of symbols for the workaround to export styles from ArcMap into ArcGIS Pro.
Copy styles from ArcMap and bring them into ArcGIS Pro
The symbology can also be saved as a layer file and the styles imported to other layers. The following documentations provide some information on that option:
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