Business visa - help with documentation

Hi

I'm a self employed, owner of a small company. I'm preparing a documentation for me and my two coworkers to apply for business visa to US. I have prepared an 'Employer's letter' for them, describing their intentions in US, that I'll be paying for the costs and other details, but I'm not sure what I need for myself, as a substitute document since I'm an employer.

I don't know what type of document/letter I need for myself, as employer and owner of a business.

Thank you