There are a variety of window options available for use in shipping containers and portable buildings that allow natural lighting, ventilation and a clear line of sight. Other window options include sliding glass panels, and security bars.
The process is generally quite easy to install windows in a shipping container – first the windows are designed and planned, then measuring, cutting holes, refining the area, and installing the windows, followed by painting them in an oxide primer then the final paint colour!
As a shipping container is a box that lets in no light without modifications, a window – even a small porthole type window – that lets in any source of natural light is invaluable, and can be done at quite a reasonable price, depending on who you get to actually do the work for you. Be sure to get at least two or three quotes from different companies – and make sure you are comparing the same things – have your plan or design worked out beforehand and shop this around with you.