A material fact is information significant to an insurer's assessment of risk or its decision about the terms of insurance. Examples can include a serious medical history, commercial use of a vehicle, or hazardous storage in a building. Relevance depends on the product and the questions asked during underwriting.
For a business in Nepal, changing an insured building from an office to a workshop could materially change the exposure. Inform the insurer and ask whether an endorsement is needed. When uncertain about a fact's relevance, disclose it clearly rather than assuming it cannot influence a later claim.