For MoI users who have a German-ID card and are interested in this
topic, I use these two services:

https://cloud.sign-me.de/signature/start
for the qualified digital signature

and
https://www.dgn.de/dgn-zeitstempeldienst/

for the timestamp.

The timestamp service can be set-up in Adobe
Reader DC, with your login-credentials, while
for the qualified digital signature you have to
upload your .pdf to sign-me.

Regards
Stefan