The following steps teach you how to download and install the tableau in your system. Tableau is available in two versions:
The Tableau public is free and open-source software that can be connected to Excel and other text file data sources, and you can publish only in the Tableau public profile. Data and Visualizations are not secure as it is available in public.
You can use the Tableau public for personal level and not for professional and enterprise level. You cannot obtain the data from the different data sources as it is connected to Excel and text files.
Tableau desktop is a professional version, you can connect this to any data sources including databases and web applications. You can save the data files as a local file and can be published in Tableau Server or Tableau Online.
The Data and Visualization are secured and the data can be extracted from various data sources and stored as a Tableau extract file.