Started as a prompt engineer

Hey, I just started on the project where I need to create prompts. The domain is finance, infotype is implicit, it includes phonenumber and creditcard expiry as fake PII data, task category is open-ended qa and prompt length is 700-2100 words. This is challenging for me because first of all the idea of writing 700 words freaks me out. Do not know what to write. Is it okay to copy texts from internet and add to the prompt? But then how can I add fake synthetic PII data there. Or how about when the domain is travel infotype is implicit, PII data is passport number, prompt length is 21-140 words, it should be in JSON-format and task category is classification. I wonder how long does it take usually for prompt engineers to create prompt which is minimum 700 words? Would be happy if somebody helped.