https://www.citizensadvice.org.uk/law-and-courts/legal-syste...
The N1 form is to be sent by post[1] and there is also an online version which can be used in some cases[2].
[1]: https://assets.publishing.service.gov.uk/media/65eb13af62ff4...
[2]: https://www1.moneyclaims.service.gov.uk/eligibility
https://www.citizensadvice.org.uk/law-and-courts/legal-syste...