If they are using Microsoft, then there is a good text to speech in MS word etc.
The Immersive reader through Microsoft as mentioned will work in Edge (the browser) as well as MS Words etc. Browsers will have their own text to speech again, look at the settings as some software are browser based.
This area has been developed quite a bit by those who create the devices. Chromebooks and Windows laptops will also have their own as part of their operating system.
What I would recommend is that you look at the settings of your device as you can select the synthetic voice used. Some are better than others or there may be a preference in the voice used. This will be device dependant but check the Settings of the device being used as well as the settings in the application they are using.
There are others that are paid for, I think some teachers of the deaf or deaf charities I linked with ages ago recommended https://otter.ai/ there is a free option, but they were looking for the closed captions to support deaf children as well as the text to speech capabilities.
Remember when using synthetic voices that there are a number of things that will effect which one is picked up and the voices do vary in quality as well as voice gender/age options
– The voices downloaded and available on the device.
– What the device has in it Settings
– What the application has in it’s Settings (browser as well as apps/ MS Word/PowerPoint etc) some software may include their own voices as well as what is available on the device