Not every digital signature is legally binding, I’m afraid.
In my country, there are 3 types of it. A simple one (login/password), unqualified (encrypted series of numbers), and qualified (same as unqualified, but encrypted using certified means by government). The last two are stored on a physical drive.
The higher the grade, the more legal power the signature holds.
When signing it by hand from a tablet it’s the same as signing it personally where I live. Which, unlike qualified digital signature, can be used for any document.