Apparently they are no longer called 'small claims' officially, but everyone I know still calls them that.

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