It is insufficient to sign a variety of documents that each require a Qualified Electronic Signature (QES) with one single QES (so-called "container signature"). Each of the documents has to be signed individually with QES (Federal Supreme Court (BGH) 2019/5/15, XII ZB 576/18).
If an electronic pen is used to sign on a tablet, neither the electronic document on the tablet nor the printout on paper will meet the requirements of secs. 126a, 126 BGB. The sections also cannot be applied analogously because the legal requirements are clear and exhaustive (Higher Regional Court Munich (OLG München), 2012/6/4, 19 U 771/12).
As a replacement for the signature, sec. 130a (1) 2nd sentence ZPO allows the use of a QES. In order to be equivalent to a handwritten signature, this signature must be made by the person whose signature would satisfy the formal requirement. In the case of an electronically transmitted statement of grounds of appeal, the QES therefore must be provided by a lawyer authorised to represent the appellant before the Court of Appeal and, for example, not a paralegal (Federal Supreme Court (BGH) 2010/12/21, VI ZB 28/10).
If a monetary restriction is entered for the certificate of a QES (e.g. "monetary restriction of EUR 100"), this does not prevent the validity of the QES (Federal Finance Court (BFH) 2006/10/18, XI R 22/06).