Hi @Anthony Javier Solano Sánchez , Thanks for using Microsoft Q&A Platform.
I empathize with your disappointment in not being able to utilize the Microsoft Azure free TTS demo without providing login credentials or credit card details. Currently, the free TTS demo is no longer available. Will share your feedback to the PG team.
But my suggestion would be, you can still try the Azure free account which includes a limited amount of free services each month. As Text to Speech is always a free service.
Here is the pricing information of Text to Speech Free tier subscription with some limitations: https://azure.microsoft.com/en-us/pricing/details/cognitive-services/speech-services/
Additionally, you can learn more about the Azure free account and the services included in the following URL: https://azure.microsoft.com/en-us/free/
I hope this helps. Let me know if you have any questions.
-Please kindly accept the answer and vote 'Yes' if you feel helpful to support the community, thanks.