The PDF extension, short for Portable Document Format Archive is an ISO-standardized (like colour management guidelines) PDF version that has been developed to preserve electronic documents in a digital way. PDFA is different from the normal PDF format in a way that the PDFA format doesn’t allow feautes that are not built for long-term archiving.
FreePDFconvert
Surprisingly exhaustive FreePDFconvert is an online PDF converter. Their service has been around since 2005 and has helped people convert