Hi, is there a way to merge separately signed PDF's in Adobe sign

Hi!

I hope you are doing well.

Once the document is signed, it is not possible to combine it with other documents. The document gets locked once you add a signature to it. This is for the security of the document.

As a workaround, you can combine the initial documents to a single PDF. Assign signature fields in the document as required and sent them for signature.
As the form fields are assigned, only that person will be able to add the signature who is assigned to that particular field.

In this way, you will have the combined copy of the documents with a signature.

I hope this information helps. This Adobe Sign guide will help you with more information: https://helpx.adobe.com/sign/using/get-started-guide.html 

Thanks,

Anand Sri.