What Contractor Insurance Covers
The core policy is general liability: it pays when your work injures someone or damages property that is not yours, such as a client's floor, a neighbor's fence, or a passer-by on the sidewalk, and it covers the legal defense whether or not the claim has merit. Contracts ask for it because without it, the property owner or general contractor is the one who gets sued.
Around that core you add what the trade needs: business equipment protection for tools, professional liability if you design, specify, or advise, cyber for the client data on your devices, and a business owners policy if you keep a shop, a yard, or inventory.
Mostly small repairs across many trades? Handyman insurance is rated for exactly that. Hiring? Workers' compensation is the separate policy you will need.