Gst applicable on goods and services both

Hi

My query is one of the dealer who was before registered underVAT has now migrated to GST. Before he was doing sales and charging VAT on the bills. He was also providing maintenance services but not charging ST he was not registered for ST (turnover didnot exceed 10lakhs) 

Now under GST If he is issuing ONLY services bill will there be GST levied on that???