I invoke \"jupyter notebook\" under:
[abigail@localhost anaconda3]$ jupyter notebook
By default, it saves to the directory of anaconda3/ with
You can save a notebook to a location of your choice by using the "File" -> "Download as" -> "Notebook (.ipynb)" option from the menu.
Alternatively you can start your notebook server from a different directory and it will save all notebooks to that directory.
A third option is to navigate to the directory you want the notebook to be saved to in the tree view "http://127.0.0.1:8888/tree" prior to creating the notebook.