Scheduled Ringer Volume Change for Work Hours Can I schedule the ringer volume to drop during work hours and then go back up at the end of work?
Yes, you can use "Do not disturb":


Go to Settings > Do Not Disturb
Enable "Scheduled"
Set your desired schedule


Your phone will be muted as long as you are within the DND schedule.

To see how exactly this feature works you may have a look at Apple's explanation for Do Not Disturb.