What can you add to ArcGIS Online?
If you have privileges to create content, you can add many different types of content as items to ArcGIS Online. You can add most item types through Content > My Content > New item. see the link:
The following table shows the types of items you can add through Content > My Content > New item. The table also indicates whether and where the item type can be displayed, as well as whether it can be published as a hosted web layer or downloaded. see the link:
@Reinaldo_Cartagena Thanks! Find my answer here for those who are interested. So the answer is no...
You cannot share a web tool to ArcGIS Online, but you can add the web tool URL published in ArcGIS Enterprise as a geoprocessing service item in ArcGIS Online. See Add items from the web in the ArcGIS Online help for more information. You can only consume the added item from ArcGIS Pro, not from ArcGIS Online.