With ArcGIS Pro, you can share your maps as web maps to your ArcGIS organization. A web map is an interactive display of geographic information you can use to tell stories and answer questions. All web maps must include a basemap. The basemap defines the spatial reference of the web map and the tiling scheme that all cached layers must follow.
All other layers in your map are known as operational layers. They can be locally sourced, such as from a file geodatabase, or they can be existing web layers. When your map is shared as a web map, the local layers are shared as new web layers. Existing web layers are not republished, and any changes made to them in ArcGIS Pro, such as symbology changes, are stored in the web map. In other words, the existing web layer is not updated.
ArcGIS Pro is a powerful design environment that gives you access to rich tools for styling and representing your geographical data. Web environments may not support all of these features, so it is recommended that you follow some basic guidelines when authoring your map in ArcGIS Pro if you intend to publish and share it as a web map.
Any bookmarks you author for your map in ArcGIS Pro are maintained when your map is shared as a web map. If you created your bookmark in a projection that doesn't match your basemap, the bookmark may not work as expected in different client applications, such as Map Viewer Classic. For best performance, create all bookmarks in the projection of your basemap. For more information, see Bookmarks.
Feature layers in ArcGIS Pro can be configured through the Locate pane to find features that match particular attribute values. When your map is shared as a web map, these configurations are maintained, so you are able to continue searching your features through other applications, such as Map Viewer Classic, without further configuration. For more information, see About finding a feature.