Write 125kHz RFID Tags

Hello all!
The goal of my project is to create a streaming identification system using RFID. To accomplish this, I purchased a couple of readers and tags. I bought the RDM6300 and the RDM630. I also purchased stickers, key fobs, and card tags.
I luckily have created a code that reads the stickers and key fobs but realized that I purchased blank cards and have to write IDs into them.
Is there anyway I can do this/anyone who could help me learn how? I have tried to do my due diligence but I can only find how to write an ID into a 13.56MHz tag.
This is my very first project so I am very much so still learning. Thank you!!

Have checked this?

Read Write HID 125K RFID tags - Arduino Forum

Hi! Thank you so much for your response.
I have checked that and unfortunately I can't find anything in that post that can help me.