A director who lives somewhere else
Directors do not have to live in the UK. Almost everything else about being one is public, and since identity verification arrived, every director has to prove who they are.
The residency question, answered
A company needs at least one director. A director must be 16 or over. Directors do not have to live in the UK, but the company must have a UK registered office address.
That is the whole rule. There is no minimum UK presence, no requirement for a UK director, and no requirement to visit.
What becomes public about you
Directors' names and personal information are publicly available from Companies House. Every director also has to give a service address, which is published as well.
If a director used their home address, they can ask Companies House to remove it from the register. That is a separate request, not something that happens automatically.
Identity verification, and the passport that works
Verification runs through GOV.UK One Login. A biometric passport from any country is accepted, and so is a UK photo driving licence, a biometric residence permit, a biometric residence card or a Frontier Worker permit.
You verify once and receive a personal code. If the company has more than one director, you need every director's code before certain filings will go through. An expired passport is not accepted at all, while an expired driving licence still works if it expired in the last 90 days and was issued by the DVLA.
One detail that wastes an afternoon: an email address can only be used once to verify an identity. Two directors sharing a company mailbox cannot both verify with it.
If the app cannot read your documents
An Authorised Corporate Service Provider can verify your identity on your behalf. That means an accountant, a solicitor or another professional supervised for anti money laundering purposes.
This is the route when you are somewhere the One Login app does not cooperate, and it is worth knowing about before you are standing in front of a deadline.
The secretary question
A private limited company does not need a company secretary. Some appoint one to take on part of the directors' work. Even then the directors stay legally responsible for the company, so the appointment moves labour, not liability.
The dates for your own company come out of the deadline calculator, and the filing itself is described in the dossier.