Where do I get my permit for Everest Base Camp?

I'm curious to know, where exactly do I need to go to acquire the necessary permit for visiting Everest Base Camp? Is there a specific office or authority that I should contact for this purpose? Additionally, what kind of documentation do I need to bring along with me when applying for this permit? Are there any specific requirements or restrictions that I should be aware of before embarking on this journey? I'm eager to make sure that I've covered all my bases and have everything in order before setting out on this exciting adventure.