Input Credit on Rent

Dear Experts

My friend has started a new company. Business is export of service.

They have office in India  and their invoice is raised on a company in Singapore ., so it is an export of service and we have taken LUT.

Now my quarries is :

1) They are paying rent for their office and landlord are giving GST bill so can they take input credit on office rent , when their output tax is ZERO.

2) If yes , then how can they claim the amount ?

Please advice.

Thanks in advance

Regards

Gupta