Sac code 998822 - job work

Under GST Job work , with SAC Code - 998822 .

1). is it absolutely necessary for the principal to be registered in order to give input/capital goods to a job worker . (Considering a situation where the principal is yet to start and register a business ? )

2). Is it compulsory for the principal to get a  challan created for job work ? Does this challan act as a contract , or a separate agreement has to be made between a principal and job worker .