What is Taxpayer's personal account (online cabinet)?

An information resource on the official website of the State Tax Committee through which the taxpayer and the tax authority exchange electronic documents. The main rules under the Tax Code: the personal account is created after the taxpayer is registered with a tax authority; information exchange between legal entities and individual entrepreneurs and the tax authorities takes place only through the personal account, while for other individuals its use is voluntary; one personal account is opened for an individual, whether or not he or she is an individual entrepreneur; access to the personal account is through the single identification system with an electronic digital signature; when the tax authority sends a document to the personal account, an SMS message is sent to the phone number indicated by the taxpayer.

Source: Soliq kodeksi, 56-modda