Alasdair Taylor's Answer

I’m not sure I understand this question.

Business letters signed per procurationem (pp) by PAs are (or at least were) very common in the law firms I used to work for. The advantage for the lawyer was that they didn’t need to be present to sign before the letter went out. Signing the letters was just part of the PA’s job. In most cases there is not much legal significance to this. If, on the other hand, a person is authorised by a company to execute contracts and other legal documents on behalf of the company, then a certain freedom of action may come along with that authorisation.