PDF timestamping
You may want to sign and put a timestamp on your PDFs in order to give them a specific date. Archiving invoices or creating e-invoices require timestamp for instance.
Most of PDF certificates include a timestamp service not guaranteed for low volumes.
The Sectigo S/MIME Mailbox-Validated and Sectigo S/MIME Organization-Validated can timestamp PDF by using https://sectigo.com/resource-library/time-stamping-server.
Sectigo also provides a time stamping service for its eIDAS certificates, see : https://sectigo.com/resource-library/time-stamping-server.
DigiCert provides a RFC 3161 time stamping server to its client certificates as well. It is available on http://timestamp.digicert.com.
But, from a certain volume of signature, a timestamping local server can be needed.
RGS / eIDAS timestamping
Some documents, such as invoices, must meet particular standards regarding signature and timestamping. TBS provides Certigna RGS* and RGS** timestamping certificates.