The qualified electronic signature (QES) is the only method recognized by European eIDAS regulations as equivalent to the handwritten signature. It is also irrefutable.
The two qualified methods proposed are .beID and itsme®.
There are other, less secure methods of electronic signature, both simple and advanced, but they do not offer the same guarantees as the qualified method.
For example, an OTP (One-Time-Password) signature is a simple and easy method, but it does not provide secure authentication of the signatory’s identity. Nevertheless, it is sufficient in most cases where the stakes are not high.
See also the itsme® blog : One signature is not the other
