In simple terms, US companies must collect a W-8 or W-9 form from every contractor payee and law firm. The W-series forms are for your records only, and not to be filed. Aim to collect these before you pay anyone. Separately, companies must file a Form 1099 for anyone W-9 contractor and law firm paid more than $600 (in aggregate) over the previous calendar year, and give a copy to the payee. There are many 1099 forms and deadlines, but it’s safest to stick to the 31 Jan deadline.
In general, if you have hired a U.S. independent contractor and paid them more than $600 in non-employment income during the tax year. Independent contractors do not include any corporations.
If you paid a law firm (e.g. Inventus Law) or someone who is not an employee, such as a subcontractor, attorney or accountant a total of $600 or more for services provided during the year.
If you have made the determination that the payee is an independent contractor, you can request the payee to fill out the Form W-9 (Request for Taxpayer Identification Number and Certification). This form includes information like the payee's legal name, Taxpayer Identification Number (TIN) or Social Security Number (SSN). The Form W-9 should be shared with the payee and stored with you for four years for future reference in case of any concerns/requests from the payee or the IRS.