Can I just display the menu without offering online order ?

Sure.
There are various options/possibilities depending what you want to achieve:

  • Just don’t display the shoppingcart anywhere. If you choose to do this, you might also want to delete any orderpage you might have (as there’s nothing to order).
  • If you still want to show the cart (to show combined prices/taxes/discounts) but want to disable ordering, go to wppizza->order settings and do not select an order page
  • you can also go to wppizza->layout and check “Completely disable online order”
  • and/or goto wppizza->gateways and disable all gateways

if necessary – depending how you want this setup exactly – you might also want to consider deleting your orderpage entirely if it’s not needed.