Which workflow can be used to create a web app using ArcGIS Online?

Create a zipped shapefile, create a web app, and share it as a web map.

Publish a web layer and add it to a shared web app.

Find or create a feature layer, add it to a map, and share the map using a web app template.

Create a web map, share it as a web layer, and add it to a newly created web app.