The first 90 days after incorporation: every letter your new company will get, in order

In its first 90 days a new limited company receives, in roughly this order: the certificate of incorporation, the Companies House authentication code, the HMRC letter with the company's Unique Taxpayer Reference, the activation details for its business tax account, and then, if it registers, the PAYE reference and the VAT registration details. Mixed in with those come the letters that are not official at all: notices from private "registers" asking for a fee. Every genuine letter comes from Companies House or HMRC and goes to the registered office, which is why that address has to be somewhere the mail is opened. This guide lists each letter, what it is for and what to do with it.

Before the first letter: identity verification

Since 18 November 2025, identity verification has been a legal requirement. GOV.UK says that when a new company is registered, the Companies House personal code for each director is provided as part of the registration filing, so every director is verified before the company exists. People with significant control provide their code when first added to the register or within 14 days of being added. Directors and PSCs of older companies have a 12-month transition that ends on 18 November 2026, handled through the confirmation statement.

There are two routes. GOV.UK One Login is free; its app route reads the chip in a biometric passport and runs a face match, with security questions from a UK credit file or a Post Office visit as fall-backs. One Login cannot always be used from abroad. The other route is an Authorised Corporate Service Provider (ACSP), an agent registered with Companies House and supervised for anti-money laundering, which checks a passport and proof of address and asks Companies House to issue the personal code. Vaulex Group is an ACSP and identity checks for up to four directors are included in its formation packages.

Letter one: the certificate of incorporation

The certificate confirms the company exists, with its name, registered number and date of incorporation. If you formed the company through an agent it usually arrives as a PDF the same day. Keep it. Banks, lenders and some customers ask for it.

Letter two: the Companies House authentication code

This six-character code is the company's signature for online filing. GOV.UK says Companies House sends it to the registered office and it can take up to 10 working days to arrive. If you formed the company through an agent, ask whether a code was set at incorporation; if not, request one through the Companies House filing service, and do it now rather than when the first filing is due.

GOV.UK's advice is to treat the code with the same care as a bank card PIN. Anyone who knows it can change the company's details online. Share it only with people who file for the company, change it when an accountant or employee leaves, and remember that Companies House will never phone you for it.

Letter three: HMRC and the company UTR

HMRC posts the company's 10-digit Unique Taxpayer Reference to the address registered with Companies House. GOV.UK says that if you have not received it 15 working days after registering the company, you can request it online. The UTR appears on every HMRC letter from then on and you need it to add Corporation Tax services to the company's business tax account.

Do that when the company starts to do business, which GOV.UK says includes buying, selling, advertising, renting a property and employing someone. HMRC's guidance is to tell it within three months of the company becoming active. You will need the company number, the date it started doing business, the date its first accounts are made up to and the UTR. An activation code for the online account is then posted to the registered office.

If the company is not doing anything yet, tell HMRC it is dormant for Corporation Tax. HMRC may then write to say it will treat the company as dormant and that no Company Tax Return is due until it says otherwise. The company must still file accounts and a confirmation statement with Companies House.

What Companies House will not send you

New directors wait for a reminder about the first confirmation statement and the first accounts. It will not come by post. Companies House stopped paper reminders in November 2020 and only sends email reminders to companies that have signed up, which allows up to four addresses including an agent. Sign up in week one.

The dates to put in the diary now: the first confirmation statement review period ends 12 months after incorporation and you have 14 days after that to file it, for £50 online. The first accounts, if they cover more than 12 months, are due 21 months after incorporation. The company also needs a registered email address, which is given at incorporation and is not published.

Letter four: PAYE, if you employ anyone

If the company will pay anyone, including a sole director taking a salary, it registers as an employer with HMRC. GOV.UK says you must register before the first payday and cannot register more than two months before you start paying people. HMRC then sends the employer PAYE reference by letter. You also receive a 13-character Accounts Office reference, which is the one used when paying HMRC.

Letter five: VAT, if you register

Registration is compulsory when taxable turnover for the last 12 months goes over £90,000, and you must register within 30 days of the end of the month in which that happened. Many new companies register voluntarily earlier. GOV.UK says you receive the registration details by post: a nine-digit VAT number, the effective date of registration and information about when the first return and payment are due. Sign up for the VAT online account as soon as the number arrives.

The letters that are not official

Somewhere between week two and week six a letter will arrive that looks like a government form. It carries your correct company number and date of incorporation, taken from the public register, and it asks for a fee to list the company on a register, confirm its details or "activate" something. It usually has a deadline, a reference number, bank details or a QR code, and a name built around words like register, registry or registration.

Companies House is direct about these: it is not connected to any of these organisations and the fee is not a real fee. Do not pay it. The only register that matters is the one Companies House keeps, and the only fees a new company owes it are the published filing fees. Genuine Companies House emails come from an address ending .gov.uk, and suspected phishing emails can be forwarded to phishing@companieshouse.gov.uk. If a letter worries you, call Companies House on 0303 1234 500 before doing anything.

Reading all of this on the day it arrives

Every letter above is addressed to the registered office. With a Vaulex Group formation the registered office is Vaulex House, every letter is scanned into the Mailroom the day it arrives and sorted into folders, with Companies House and HMRC mail kept apart from the rest. Your accountant can be given gated access to just those folders, so the UTR letter and the PAYE reference are in their hands the day they land, and the "register" letters are filed where they belong.

This guide is general information, not legal or tax advice. Ask your accountant about Corporation Tax, PAYE and VAT decisions for your own company.

Start when you are ready

Form your company with Vaulex Group at https://vaulex.co.uk/company-formation/, with identity checks for up to four directors included and the registered office at Vaulex House from day one, within one working day. If the company already exists and you want to know whether its directors and PSCs still need to verify, run the free checker at https://guides.vaulex.co.uk/am-i-affected ("Check my company").