My iPad has ringer sound but no screen sound

There are essentially two controls for volume, one being for most audio (adjusted using the physical volume control buttons of the iPad) - the other being for the ringer, alerts and sound effects such as the lock sound (controlled from iPad Settings - and, sometimes confusingly, also the physical volume buttons).

For system ringer and alerts:

Settings > Sounds > [Ringer & Alerts] - adjust the volume slider as required

You can enable/disable the Change with Buttons setting - as this allows you to alter the alerts sounds using the physical volume buttons in some circumstances. Many Users prefer to leave this disabled - as doing so reduces the chance of accidentally changing the either the main audio volume when trying to change the notifications volume, or vice-versa.

Also note that you can both adjust and mute audio volume using the iPad Control Centre. To do so, swipe-downwards from the top-right corner of the screen to expose the control centre and its volume controls:

Pay attention to the three settings outlined in red - as each will impact what you hear - if anything - from your iPad.

More information about the various controls can be found here:

Adjust the volume on iPad - Apple Support

Hopefully this clarification will be helpful in determining the cause of any difficulties with your audio volume settings.

Hello

if your sound is not working try restarting your iPad Restart your iPad – Apple Support (AU)

or look at this If you can't hear any sound or hear distorted sound coming from your iPhone, iPad or iPod touch speaker – Apple Support (AU)

What exactly do you mean by no device sound?