Hi I'm new to Adobe products especially to Digital Signature. I've got questions regarding security and I know many people are using it but would like to hear from the experts and people using this program.
Can anyone advice how safe is to use the Sign function under "Fill and Sign" which comes free with Acrobat Reader DC? Is it possible for someone else to copy or use the digital signature that is not belongs to them?
A digital signature has two parts, one public and one private key. When you sign, only the public part is in the PDF. You must protect your computer and your private key.
Note that an on-the-page signature like on paper can always be stolen in seconds, and is worthless for security.
You must use Tools > Certificates, not Fill&Sign.