The "Record number" field is a field that displays record numbers. Record numbers are sequential numbers that start from 1 and are automatically assigned to each record every time a new record is added.
When you place the "Record number" field on the app form, the record number is displayed on the "Record Details" screen of each record.
Record numbers cannot be changed. Record numbers of deleted records are skipped and will not be re-assigned to other records.
Even when the "Record number" field is not placed on the app form, record numbers are automatically assigned to records.
Record numbers are displayed when the (All records) view is selected on the "View" screen. Also, record numbers are included in the URL of each record in the following format: "show#record=record number". It is also possible to use record numbers as a filter condition to narrow down the records.

• Record numbers are assigned sequentially. You can use them to distinguish each record.
  For instance, in a task request app, you can change the name of the "Record number" field and use record numbers as request numbers.

• If you use the App Code feature, a record number combined with the code to identify the app is displayed in the "Record number" field. For instance, if you set "client" as the app code, the "Record number" field will show a value such as "client-1". When you enter a record number that contains an app code in kintone apps or spaces, it turns into a link to the corresponding record.
  For instance, if you set an app code in a customer management app, you can easily create a link to a specific customer's record by writing down the record number together with the app code into comments in apps or spaces.
  Setting an App Code
  
  

• The "Record number" field can be set as the copy source for Field Mappings in "Lookup" field settings.
  You can use record numbers to find out which record data in the reference source app (Datasource App) is retrieved by the "Lookup" field.
  Configuring a "Lookup" Field

• Name
  • Specify the label for the field.
• Hide field name
  • Hide the field name on the "New Record," "Edit Record," "Record Details," and record printing screens.
• Field Code
  • A string used for specifying this field in APIs.