Hi,
Do you validate identity for PDF signing, I generated SSL Key to sign a document, but when I open the doc, there is a warning because the certificate has been self signed when I created the keys.
Longer answer: because Let's Encrypt is fully automated, it can only validate things that actually are automatable. Identity isn't really one of them. There are of course numerous ideas that one could think of (there are third party services out there which can "parse" an ID card and thus "identify" someone for use by a company [for example, I was required to upload a photo of my drivers license to be able to fully automated rent an electric shared scooter from a company called Go Sharing]). However, this is not something Let's Encrypt offers nor do they plan to offer such a thing in the future (to my best knowledge). The Let's Encrypt certificates are only used to encrypt TLS connections, not documents.