I always wonder if there would be a simple app which could simplify text-to-speech and convert bunch of stories, text, podcasts and audios to speech. I found some websites which could help you do just that:

First on the list is:
text2speech.dev

I find text2speech.dev to be really nice as they allow to Try out live demo without logging in, or login to enjoy all SSML (Speech Synthesis Markup Language) features. SSML IS XML-based marketup language, more info here https://en.wikipedia.org/wiki/Speech_Synthesis_Markup_Language

Of course, other alternatives are also good

voicemaker.in
text2speech.org
text2speech.us
ttsreader.com

I hope you found this post useful and feel free to try text2speech if you are in need for online converters.