Companies House have begun circulating emails to people regarding verifying your identity. This is being implemented to prevent people intending to use companies for illegal purposes.
If you are a director of a company, a person with significant control (PSC) or a company secretary who submits company documents, you will be required to verify your identity. Although this is currently voluntary, it will become a legal requirement in time.
You can do this online using your gov.uk account or in person at a post office. Once verified, you will be provided with a Companies House personal code which you will need in order to submit documents such as confirmation statements, and for connecting your identity to Companies House records.
More information on this subject can be found here:-