Content: Esri, the developer of ArcGIS Pro, has created a YouTube channel for users to learn the software. Not only tutorials of ArcGIS Pro, this channel has various contents on ArcGIS such as Smart Mapping, Story Maps, and more. Beside watching videos, Esri also provides step-by-step tutorial online.
Content: These are lecture series from SabberFoundation, lectured by Md. Sabber Ahamed, Jahangirnagar University, Bangladesh, on some in-depth GIS functions, such as import and export excel data, georeferencing and spatial analysis.
Esri's MOOCs offer free online classes on the latest development of the ArcGIS system. Those classes are available day and night, taking around a few hours every week. After completing the course, a certificate would be presented.