Voice Record Pro is an app I recently added to my own iPad to compare it to iRig Recorder, the app I had previously been recommending to teachers that who were interested in an app for simple voice recording.   Here are some screenshots from inside the app:
When you first open app you’ll see a list of your saved recordings and on the upper right the recording controls:

When you first choose the red “Record” button,  screen looks like this:

You can “Check Level” to make sure you’re getting a clean recording, then tap “Start” to actually begin recording and the screen shows a moving needle indicating recording:

Once you’re done and click “Stop”, you’re presented with a screen like this one where you can change the default file name from the date and time to whatever you’d like the file to be called: