How can we claim Gst input?

presently only exporters are getting refund for other refund process has not been started yet. when it comes you can take refund.

No u can't claim refund , plz ref. sec 54 Cgst act
below few condition, refund can claim
Export of goods or services.
• Supplies to SEZs units and developers
• Deemed exports
• Refund of taxes on purchase made by UN or embassies etc.
• Refund arising on account of judgment, decree, order, or direction of the Appellate Authority, Appellate Tribunal, or any court.
• Refund of accumulated Input Tax Credit on account of inverted duty structure
• Finalization of provisional assessment
• Refund of pre-deposit
• Excess payment due to mistake.

I also agree with Mr.Pankaj version

it's may be you are correct in your sense but let's take an example that suppose I am manufacturer my raw material GST rate are higher than my finished good product suppose in this case I have more ITC available . then what circumstance may happen.

yes, this scenario comes under "Inverted duty structure", you may get upto 60%... only

Sir , for inverted tax structure the council has prescribe the list , if u fall under it then only u can claim refund under it

Are all exporters getting the refund?