Hi at all... i would like to export my digital signature from my Acrobat Reader but i saw a strange behavior...When a go to Preference->Signature->Identities e Trsut Certificate and i do the procedure for to export, i have the possibility to export signature on fdf, p7c or cer file... when i try to create a new signature and i choose import a file, the only possibility that i have is p12 or pfx file... Now, why the export is same type of file and import another type? If i export my signature is because i want after to import in another computer right? How can i export the signature in right format?
The Export exports only the public key. For the Import you must look for the .p12 or .pfx file on your system.
This is an awful answer. The OP followed the original instructions on the Adobe website which do not provide the necessary information to successfully accomplish the transfer of the certificate for anybody with only a basic understanding of the topic (https://helpx.adobe.com/acrobat/using/trusted-identities.html). This answer barely hints towards a practical solution.
The help topic shows the functions for export and import of public keys.