You have to send birth certificate, nagarikta won't do in this case. You do not send any originals unless specified. You have to send a copy of your birth certificate. If it is in Nepali, you will have to get it translated and send copies of both nepali and english. So far I know, IELTS scores, police report are only the originals they ask. Everything else, you should send copies. You don't even have to notarize.

Your local VDC or municipality can make a birth certificate. You have to call your parents or relatives back home and ask them to make it. Most issue in Nepali so you will also have to go to Kitab Khana in ktm to get it translated.