I just took my time to lean everything about the vector tile layer. And the documentation is really shattered; but my most important places are:
You can host your own.
Once your map is complete, you're ready to create vector tiles. To do this, you share the map as web layer.
Alternatively, you can use the Create Vector Tile Package tool. This tool will generate a complete vector tile package, a .vtpk file from a map or a basemap. You can then share and use the vector tiles in ArcGIS Online or Portal for ArcGIS.
Whether you make vector tiles by publishing a web layer or using the geoprocessing tool, there are a few decisions you need to make prior to creation.