I've been working as a freelancer for 4 years. Now I want to move to a permanent job.
The company where I'm applying for this permanent job is requesting a document that prove my work of at least 1 year.
In the last 2 years of my freelancer work, I've been working using 85% of my time for an important client.
What document I can ask for from this client to prove my work? Since most of my time I spent developing projects for him (Taking into account that at no time we had a contract involved).
Is there any document similar to a "Certificate of employment" that matches my situation?