A digital signature is a mathematical technique which validates?

Enabling digital signature in documents is not an exclusive feature of Adobe, one can enable digital signature in a document without using Adobe Reader DC using the following tools:

• PDF Documents:
  • Foxit PhantomPDF
  • Nitro PDF
  • Smallpdf
  • LibreOffice
  • DocuSign
  • HelloSign
• For Office Documents:
  • Microsoft Office
  • OpenOffice/LibreOffice

To add a digital signature to a PDF, follow the steps given below:

• Open the PDF in Acrobat Pro
• Choose the Tools tab or side menu
• Press the ‘Fill & Sign’ option
• Select Sign
• Click on ‘Add Signature’ from the ‘Quick actions’ toolbar
• Input your signature by either typing it, drawing it or uploading an image of the signature
• Hit Save
• Drag and drop your signature into the desired location in the document
• Hit Apply
• Select Digital IDs (Windows) or Save a Certified Copy (Mac)
• Log in to Adobe or a different login service
• Input your credentials
• Press the signature field
• Select your digital ID
• Press Sign
• Input your password or PIN

Some of the free open-source digital signature software that can stamp a signature onto the document and save it are as follows:

• JSign
• OpenSC
• Cryptomator
• LibreOffice
• PDF-Shuffle

Some of the best eSigning software for Dot net Application are as follows:

• Adobe Acrobat Sign
• DocuSign
• SignWell
• SignNow
• ESignatures.io

• To create a digital signature in Word, you can use the built-in feature.
• Go to Insert > Signature Line and follow the on-screen instruction to create digital signature.