The CAD files in DGN and DWG format are frequently used to store drawings of engineering projects. A single DGN or DWG file can encompass line, point, polygon, and annotation layers. You can add DGN or DWG data in ArcGIS Event Editor using the following steps.
Note:
- You need a DGN or DWG file and a PRJ (projection) file with the same name to add the data to the map.
 - The DGN or DWG file remains in the map until the end of the browser session.
 
- Open Event Editor and, if prompted, sign in to Portal for ArcGIS or ArcGIS Online.
 - Click the Map tab.
 - In the Contents group, click the Add Data button 
.The DGN and DWG options appear.
 - Choose an option for adding a file.
- Click DGN to add a DGN file to the map.
 - Click DWG to add a DWG file to the map.
 
 - Click Next.
 - Browse to the folder containing DGN or DWG data and select one DGN or DWG file and one PRJ file with the same name.
 - Click Open.
 
The DGN or DWG data is added to the map.