Praat is a free, open source software package for research and/or clinical practice. This powerful software has been developed by Paul Boersma and David Weenink, Phonetic Sciences, University of Amsterdam.

State-of-the-art voice/speech clinics through sophisticated and high-quality yet accessible acoustic voice/speech analyses. Commercial web site

The above PDF shows an analysis of my voice from a reading of The Rainbow Passage (Fairbanks, 1960) using Praat and the Phonanium plug-in. The use of the Rainbow Passage allows a more accurate overall pitch range and median to be calculated.

Reference
Fairbanks, G. (1960). Voice and articulation drillbook, 2nd edn. New York: Harper & Row. pp124-139.

A free plug-in with automated scripts for voice processing by Ramon Corretge.

This includes the Change pitch median and variation where voice recordings may be altered to a required pitch.

Download and installation guide.

Cepstral Analysis is increasingly used clinically "…as an objective measure of breathiness and overall dysphonia." (Murton Hillman & Mehta, 2020).
Saunder, Brett & Eadie concluded that "…these studies support the robust nature of CPPS to detect dysphonia, including disorder status as well as perceived dysphonia, in a variety of different patient populations." (2019, p. 564)

An anagram of 'Spectrum', can be thought of as a spectrum of a spectrum. The cepstral peak prominence (CPP), or smoothed CPP (CPPS) may be calculated using a free plug-in (see below), or a paid-for plug-in by Phonanium (with more detailed statistics and graphical representations of the analysis).

A free plug-in for Praat by Elizabeth Heller Murray (2022). The plug in provides figures relating to a voice sample for CPP (Free).

James Curtis, PhD, CCC-SLP has a very helpful 'walk-through' for Praat functions for Voice Analysis.

Speech, Hearing & Phonetic Sciences, UCL have free, online software, including real-time amplitude and pitch display.
See here for the links to all web-based apps.