After the installation, the ArcGIS package can be found in a separate folder named arcgis followed by the version number inside of the C:UserNameAnaconda3pkgs folder. If you have the API already installed on your computer, you might need to update it to the most recent version to ensure everything is working correctly, such as the map widget:

conda upgrade -c esri arcgis

The most recent version of the API at the time of writing is 1.4 and requires Python 3.5 or higher. You can test your installation by opening the Jupyter Notebook app, as follows, from a terminal or run the application directly from Anaconda3:

jupyter notebook

Then, run the following code and check to see if a map window opens up and you receive no error messages:

In: from arcgis.gis import GIS
    my_gis = GIS()
    my_gis.map()

If you have ArcGIS Pro installed, then you can install the API by using the conda environment inside Pro, using the Python package manager. Look for the Python tab and click on the Add Packages button. Search for arcgis, click Install, and accept the terms and conditions.