Some Tech Help Needed

I do not do the internet on any type of mobile device so I know very little about how it differs from using a PC. I do quite a bit on ebay and that is where my problem is coming in. If anyone here does ebay by mobile device is there a way for a buyer to put multiple items into their cart and then to request a combined shipping total from the seller before they pay for their items? I seem to be having a problem with buyers who cannot find the request total button. Any help/advice would be appreciated. Thank you.

Randy Goodling
CCOA #95

By chance due you have the items listed with a required immediate payment?
“If you want your customers to have the option of purchasing several items from you and getting a combined invoice from you, you have to “un-check” the require immediate payment with buy it now option in your listings. If you revise your listings, it is under your selling details section in the payment options area.”

I found this info listed here
https://community.ebay.com/t5/Buying/a-buyer-put-items-in-his-cart/td-p/30120909

Hope it helps,
Paul