Export sample

If you want to know accounting entry:-

Dr. Expenditure A/c (eg. if it's sent for Demonstration purposes, you can use Advertizement / Demonstration / etc.)

Cr. Inventory A/c (with the cost of the material, not the price of the material)

EXIM perspective:-

You will have to declare in the Export Invoice that this is a Free of Cost material sent for XYZ purposes. If it's chargeable to Export duty, Assesment will be done (bill of export) and duty will be payable.