Can I publish a map from ArcMap (Desktop) to ArcGIS online without belonging to a larger organization/ without a server URL? I am a freelancer and on my own in this great big world.
You can use 'Add item' in ArcGIS Online and share. See the link below for what you can add and notes
https://doc.arcgis.com/en/arcgis-online/reference/supported-items.htm
Hello!
Unfortunately, you cannot publish content from Desktop to ArcGIS Online with a public account. However note from the following documentation: FAQ: Can a user with a public account publish hosted feature services to ArcGIS Online
"Users can still upload data to their ArcGIS Online account using their public accounts by exporting the feature classes as a shapefile and zipping it using Windows Explorer. However, only 1,000 features can be uploaded."