Electronic signature or digital signature: what is the difference in a PDF?
A drawn signature and a certificate digital signature are different things. What each is, how to digitally sign a PDF on a Mac, and how to know which you need.
An electronic signature is a picture of your signature on the page. A digital signature is a certificate based seal that proves who signed and shows if the file changed. People use the two terms as if they mean the same thing; in a PDF they do not, and a Mac makes only the first one on its own.
What is an electronic signature?
A picture of your signature, or your typed name, placed on the document. Signing in Preview, on your phone, or in most online signing services gives you this. Many organisations accept it for everyday agreements. How to sign a PDF on a Mac shows how, for free.
What is a digital signature in a PDF?
A cryptographic seal made with a certificate that proves who signed and shows if the file changed afterwards. Readers that support it show a banner such as Signed and all signatures are valid. You usually need a certificate from your employer, a government ID scheme or a certificate provider, and software that supports it.
How do I digitally sign a PDF on a Mac?
You need two things Preview does not provide: a certificate, often called a digital ID, and an app that signs with it. If your employer, bank or government gave you a certificate, they usually also name the app or portal to sign with. Adobe Acrobat Reader, which is free, can sign with a certificate you already have. Preview cannot add a digital signature at all.
How do I check a digital signature in a PDF on a Mac?
Open the file in an app that checks certificates, such as Adobe Acrobat Reader, and look for the signature banner or panel. Preview shows the page, including the visible part of a signature, but not whether the certificate behind it is valid. That is also why a digital signature can seem to be missing: the app you opened it in does not show it.
Which one do I need?
Ask whoever asked you to sign. If they say sign and return, a drawn signature is usually what they mean. If they mention a certificate, a qualified signature or a specific portal, they need the digital kind. Whether either is legally valid depends on where you are and what the document is.
On a Mac
Preview adds electronic signatures for free. Simply PDF does too, writing saved signatures into the page so they show in every app; Fill and Sign needs a key. For certificate signatures, use the tool your employer or the requesting organisation provides.
Questions
How do I digitally sign a PDF on a Mac?
You need a certificate (a digital ID) and an app that signs with it, such as the free Adobe Acrobat Reader or the portal your organisation names. Preview cannot add a digital signature.
Is a signature added in Preview a digital signature?
No. It is an electronic signature, a picture of your signature on the page. A digital signature uses a certificate to prove who signed.
Is an electronic signature legally binding?
Often, but it depends on your country and the document. Ask the person or organisation that needs the signature what they accept.