Here is the List of Supported Custom Fields Types in Paperless-ngx:
Text: any textBoolean: true / false (check / unchecked) fieldDate: dateURL: a valid urlInteger: integer number e.g. 12Number: float number e.g. 12.3456Monetary: ISO 4217 currency code and a number with exactly two decimals, e.g. USD12.30Document Link: reference(s) to other document(s) displayed as links, automatically creates a symmetrical link in reverseSelect: a pre-defined list of strings from which the user can choose
NOTE
Refer to Paperless-ngx documentation - Custom Fields for more information.