Bloomz allows admins of the schools to bulk import the members in the following ways. 

Bulk CSV Import:

Bulk Import of Students and Parents to the school using a CSV file upload

Bulk Import of Teachers to the school using a CSV file upload?

Bulk Data Import Using CSV Files In A BrowserManual/CSV Transitioning to the new school year - School Admins 

SFTP Import:

SFTP Bulk File Export Instructions

Bulk Data Import Using SFTP

Clever Import:

Clever School Integration - A Guide for School Admin

Clever Autosync for Administrators