rcm applicable

Yes, compulsory registration u/s 24(iii) of the CGST Act for persons who are required to pay tax under reverse charge.

Liability to pay tax under rcm is applicable only when recipient is registered. If recipient is not registered than tax liability will be pass on gta service provider.

compulsory Registeration for toh hmko bhi registration krna padega

GTA services to an unregistered person is exempted as per Notification No. 32/2017- Central Tax (Rate) dated 13th October 2017. However, this notification is cancelled as of 31st Dec 2018 and hence, tax must be paid under RCM for unregistered purchases on the notified list of supplies. However, the list is yet to be notified.

to kya RBI Ko bhi registration krwana padega as case of Rcm

You have to register compulsarily if GTA charging tax @ 5%