Clearly you have completely exhausted available internal storage - and your iPad is unable to operate as expected.
If the Voice Memos setting is not visible/accessible on the iPad, instead disable Voice Memos in iCloud on your iPhone. This will remove disable synchronisation of the iPhone with iCloud - and will retain a copy of your Voice Memos on the iPhone.
Next, delete the Voice Memos App from your iPad - in so doing deleting all associated data from both the iPad and iCloud. After deleting the App, perform a forced-restart of your iPad:
Force restart iPad (models with Face ID or with Touch ID in the top button)
If your iPad doesn’t have the Home button, do the following:
- Press and quickly release the volume button nearest to the top button.
- Press and quickly release the volume button farthest from the top button.
- Press and hold the top button.
- When the Apple logo appears, release the top button.
Force restart iPad (models with the Home button)
Press and hold the top button and the Home button at the same time. When the Apple logo appears, release both buttons.
After the restart, verify your available storage on the iPad.