How to delete documents and data for iPod Touch apps for space without deleting the apps and reinstall them?

One way to do this for all of your apps is to connected the iPod to iTunes and restore it to factory settings versus restoring from a previous backup.

iTunes: Backing up, updating, and restoring iOS software

Otherwise, you'll need check each app to determine if they have a way of deleting/removing it's app specific data.

B-rock

Planb77 - helpful reply. But very unfortunate. I have a new iPod touch. My ONLY use is to stream music from Apple Music, Pandora and similar apps to my bluetooth speakers. Within 48 hours my documents and data junk has grown by 2GB. I have no locally stored files. No photos or videos. Mail, messages, facetime, notifications, background refresh and everything else have been turned off or disabled.