How can you prove you've done freelancing work if you don't have a standard document or certificate?

I’ve been doing some freelancing work on the side but don’t have a standard document or certificate to show as proof in an interview. How can I prove that I’ve done this work?

One way is to provide potential employers with a portfolio of your work. This can be a collection of writing samples, design projects, or any other type of work that you’ve done as a freelancer. Another way to prove your freelancing experience is to provide references from clients or other professionals who can attest to the quality of your work. Finally, you can also provide tax records or other financial documentation that shows you’ve been paid for your freelancing work in the past. By taking one or more of these approaches, you should be able to successfully demonstrate your freelancing experience to potential employers.