Quoting its presentation page, Azure TTS is “a Speech service feature that converts text to lifelike speech”. Being offered as a cloud service by Microsoft, it supports over 330 voices in more than 129 languages, providing voice variants with different styles and emotional tones to make them suitable for different usage scenarios (text readers, support chatbots, ETC.).
Of course, it allows to fine tune speech parameters such as pitch, rate, intonation, and pause duration. Many customizations can be done by means of Speech Synthesis Markup Language (SSML). Different deployment strategies are supported, and the service web page includes an interactive applications you can use to demo all voices and parameters.
Finally, Microsoft Azure TTS can be leveraged to create unique, fully customized voices.