Ulym - This link explains the difference between secured and unsecured debt.
https://www.investopedia.com/ask/answers/110614/what-difference-between-secured-and-unsecured-debts.asp
and this one has a bit about trade creditors. Trade creditors are typically unsecured creditors (just the way business works).
https://www.skillmaker.edu.au/trade-creditors/
(not sure they are the best explanations out there but they are a starter - apologies if I'm telling you how to suck eggs).