Within the website is a copy of the Arizona Residential Landlord and Tenant Act. Here is a direct link to the page where you will find this document:
You can copy and past these link to your web browser. Within this document you find information relative to the protocol for the established code of procedure or behavior between Tenants and Landlords.
Best of luck,
The person who gave you the papers is a hired contractor to serve as Process Server.
It does sound strange the papers did not say why, or you don't know why. That would be good information for anyone here or the attorney you might end up hiring.
You do have certain rights as a tenant with a lease, if the cause is the landlord is going through a foreclosure, as follows:
Federal Tenant Protections
Under the federal Protecting Tenants at Foreclosure Act, a new owner cannot evict a tenant for at least 90 days after foreclosure. And unless the purchaser intends to live in the home as a primary residence, the tenant can stay until the end of the lease term.
Not knowing what the circumstances are behind your eviction notice, it's difficult to answer your question. Because you have been served with a 5-day vacate notice, you have most likely not paid your rent on time or otherwise breached your lease agreement. If that is the case, the answer to your question is no, the notice does not have to be from a court or stamped by a judge. The owner simply needs to document the delivery of the notice and that you were in receipt.
It sounds to me like something went down between you and the landlord. However, now that you have been served with a notice, if you don't vacate you will be evicted and have a judgment on your permanent record that will make it all but impossible for you to rent a property in the future. I would suggest working out the differences with your landlord. If you can't do that, then your only other option is to vacate immediately.