https://osvita.ua/master/master-zno/rez-master/89706/ - here is information about the 2023 TZNK.
According to national legislation, those liable for military service must submit documents confirming the right of citizens to a deferral from military service to the district (city) territorial recruitment and social support centers by October 1 each year.
If you mean Article 23 of the Law of Ukraine "On Mobilization Training and Mobilization", then it concerns the categories of military personnel who are not subject to conscription during mobilization. You can read more about the article at the link: https://zakon.rada.gov.ua/laws/show/3543-12/conv#Text.