PDF Signing Questions

[Carlisle1500]

In the past, I have digitally signed my documents to send to someone else. Recently, I had an NDA sent to me and tried to sign it but I was not allowed to. 

1. How should signing a document work?  The only way I got this work was by saving a local copy of the signed senders document and then signing it and sending it back. 

2. Is there a way to do this in real-time like docusign?They allow you just click, sign a document, and send it back. Do I need other adobe software installed. I have CC all apps install now and was signed in. 

See screenshot of the issue I had: 

[try67]

Yes, it's possible, if they use Adobe Sign. If they expected you to use a digital signature field then you have to sign the file, then send it back to them manually.