Can I send a regular mail from UK to UK, but print out US FROM address?

Question

a friend asks me that she has a 150 pages of documents to send out to UK from US it will cost her a lot, so she said, I can send you that in PDF, why dont you print it (in England) and ship it form England locally will cost you less (of course, that mail does not have to travel entire world) but she said put my American address in a "FROM" field on the envelope.

Question: what will the post office say? wil lthey reject? or they dont care about from? (it will be sent from local UK post office)

Answer 1

Why doesn't she eMail it in the first place?