Questions about Job application via Hello Work

I am job hunting (part time) via Hello work. In my first visit they given me some postings matching my request. However, since my Japanese isn’t good they asked me to contact the company before I make application. If company is okay,then go to Hello work to initiate the application process.
So here it goes. Job posting states it requires applicant’s CV, career history, ハローワーク紹介状(Hello work’s letter of introduction). I contacted the company and they are okay with my application.In addition when I introduced myself (with my CV) they scheduled an interview. I said I am yet to obtain ハローワーク紹介状. They say there should be no problem however to be sure check with Hello work. In this case their scheduled interview date is well before my next appointment with Hello-work. I can only get that ハローワーク紹介状 after interview unless it’s a too simple thing to walk in and get it without interpreter/appointment (I already have hello work applicant number).

This is my first experience with Hello work thing and I am not sure how important is ハローワーク紹介状 in both Hello work and company’s perspective.

Another question is what is career history. My work history is already included in my CV (& FYI I don’t have any work history in Japan).