You pay someone like Trinet [1]. You wire them funds, they distribute to employees in all 50 states and handle payroll, taxation, etc. They act as the employer as record, show up on employee W2s, etc. There are other companies out there that perform the same service, but Trinet is the company I'm familiar with having worked at a fully remote startup.
If you have international employers, there's more complexity besides wiring them funds; you have to ensure you're not violating local labor law as it relates to employee vs contractor classification. Talk to an attorney!