What's a good online fax service that's secure and easy to use?

I tested six different fax services last year when my company went fully remote and our ancient machine finally gave up. The first one I tried looked professional but had a confusing dashboard that took me twenty minutes to figure out how to upload a file. The second one worked fine until I realized they limited me to five pages per fax, which is useless for legal contracts. What I actually needed was something simple enough that I could use without a manual but secure enough for client information. That's when I focused on three specific criteria: delivery receipts so I know my document arrived, transparent pricing without hidden fees, and the ability to send a fax from any device because I'm not always at my desk. I also learned that services with HIPAA compliance tend to have better overall security, even if you're not in healthcare. Another tip is to test their customer support with a basic question before committing. If they take days to reply, imagine how they'll handle a real emergency. The service I settled on gives me a confirmation number for every transmission, and that alone reduced my anxiety about lost documents significantly. The free tools for merging PDFs and adding cover sheets saved me from using separate apps too.