For others who find this thread useful can refer and vote for this Feature Request, which would be really useful in setting a user role and other fields.
e.g. As User A invites User B to join their Organisation, I would be able to set User B’s Organisation as User A’s Organisation through the add automatic field.
Creating a list of a button works if you have only one field, otherwise, you need multiple buttons of lists to set different fields to a default value.