Tableau Exam Desktop-Specialist Topic 1 Question 54 Discussion

You can add reference lines, bands, distributions, or (in Tableau Desktop but not on the web) box plots to any continuous axis in the view.

Reference Lines - You can add a reference line at a constant or computed value on the axis. Computed values can be based on a specified field. You can also include confidence intervals with a reference line.

https://help.tableau.com/current/pro/desktop/en-us/reference_lines.htm