The (austrian/german/mostly european) laws governing data protection and data security keep personal data of living and non-living individuals private.
The official documents are free to the public either 100 year after birth, 75 years after marriage or 30 years after death.
But "free to the public" don't mean that they are automatically published, normally you have to request them. An exception are the parish registers before ~1917 (note the 100 year period from above!), these are already published online.
So, within the above time ranges, you can get informations only
a) if the individual (or someone else) had published the information itself, e.g. an obituary in the local newspaper, telephone and address data in the phone book,
b) another relative that had requested the official documents by himself, and provide them to you,
c) anyone published memories of the person (this can includes a photo of the headstone at the cemetery, as this is no "official" document)
c) you are a direct relative of the person and can request a copy of the official documents.
There are tendencys toward recording actual gravestones from cemeteries, but this will be entirely done by volunteers, if ever. I'm not aware of any organization that organizes this.
To make matters worse, headstones/graves must be 'rented' (normally 25 years). After that period---if no relative will pay the fee for another 25 years---the grave will be vacated and the headstone removed. This is done because the parishes in Europe facing a space problem (cemeteries in Europe are far smaller than those in America!).
Finally, that means
- if you are a relative to the person, try to request the official documents (this is the preferred way, because the information would be reliable!);
- if you know relatives of the person, write them and ask;
- if none of the above, you are much or less lost. Your only chance is to search for some tertiary information at e.g. FindAGrave.com (but don't expect much), Newspapers (obituaries), Facebook, Telephone registers (e.g. https://www.herold.at/telefonbuch/). But don't expect much, since you are normally unable to connect persons or relatives with it!