There are many text-to-speech options available, from websites, to browser extensions, to purchased software. Here are my two free favorites at the moment:
Chrome (web browser) Extension: Read & Write for Google Chrome
Appears as a button within their Google Docs or a button on their URL address bar for websites. See it in action:
Copy and paste text, choose your accent/reader, then press play! See it in action:
Walk your students through adding the Read & Write extension to their Google Chrome account. They will need to log in to Google Drive and accept the permissions (just once) in order for the extension to work. Help them bookmark TTSreader.com for quick access when needed.