Hi,
Companies are incorporated in the UK through Companies House (which is a separate office to HMRC) and you should contact them in the first instance regarding forming a company while not resident in the UK.
Information when
setting up a limited company which you may find useful, particularly under "register as an overseas company" which advises that you do not need to register if you do not have a base in the UK.
A company registered for corporation tax is required to submit company tax returns, statutory accounts and computations anually.
There may also be requirements to register for other taxes such as VAT.
It is not really possible to list all necessary requirements in a hypothetical situation and I would recommend taking independent financial advice regarding your obligations.
You will need to establish, for example, whether you will have economic activity in the UK.
There is a difference between a non-resident company that is trading from abroad with customers in the UK, and one that is actually trading in the UK.
Thankyou.