Please guide us gst rcm applicability on transportation on supply made to merchant exporter

If transporter raises the bill in your name and not charging GST in the invoice. And transporter is GTA & charges >Rs. 750/1500 then you need to pay RCM on the same

As per Notification 9/2017 IGST (r)
GTA services are exempted only when:
(a) agricultural produce;
(b) goods, where consideration charged
for the transportation of goods on a
consignment transported in a single
carriage does not exceed one thousand
five hundred rupees;
(c) goods, where consideration charged
for transportation of all such goods for a
single consignee does not exceed rupees
seven hundred and fifty;
(d) milk, salt and food grain including
flour, pulses and rice;
(e) organic manure;
(f) newspaper or magazines registered
with the Registrar of Newspapers;
(g) relief materials meant for victims of
natural or man-made disasters, calamities,
accidents or mishap; or
(h) defence or military equipments.

Hence in your case RCM is applicable if the bill is in your name & you are paying, else the recepient