5 volts or 10 volts USB charging wall plug

The supplied iPad charger supplies 10 watts not 10 volts. It supplies it at 2 amps. The USB charging voltage is 5 volts. What specific "5 volts wall plug" are you planning on using? The iPhone charger puts out 5 volts but on 1/2 watt so its power is only about 5 watts.

You can use either the smaller iPhone charger or the included iPad charger. Both will work.

I've been using my iPhone charger since it's already plugged in with a cable attached 🙂.

An iPhone type (5 watts) will work but will take about twice as long as using the 10 watt charger supplied with the iPad. Also, the iPhone charger may not show that the iPad is charging but it will charge with the iPad is sleeping.

The iPhone AC charger shows that the iPad is charging.

I haven't seen that yet. Every iPhone charger i've connected the iPad to charges only when it
It's asleep and very slow. I bought a couple of extra iPad chargers that i use for both now.

I've been plugging in to my iPhone charger and it shows charging.

Same on mine. The iPhone charger shows charging when awake.