So I was doing a freelancing project for my client, but I do not own a company for my services. When comes to invoicing I can create my own title but the problem is, it is still not under a registered company.

My client has an issue with my invoice as it is not a legit company, as it might face auditing issues.... Is there any way to overcome this? Like going through a 3rd party company or a freelancing portal that doesn't incur additional charges?