Compliance with the plan eliminates the tax’s regulatory target, so it can’t be evaluated for future use.

Therefore, due to the fact that this issue has not been sufficiently studied in the science of financial and tax law, it is difficult to make a clear distinction between the meanings of the concepts "object of taxation" and "tax object." At the same time, one should agree that the presence in the legal doctrine of the category "tax object" along with the object of taxation is necessary. In this connection, in this article the terms "object of taxation" and "tax object" are considered as synonyms. If you turn to property taxes, for example, to the tax on the property of individuals, then residential houses, apartments, rooms, car places, etc. with ownership of these objects are the object of taxation. In this context, it is rightly noted that the right of ownership, which is the basis of personal rights and freedoms, also serves the public interest of taxation. The object of land tax is land plots that are both in the ownership right and owned by taxpayers on the right of permanent (unlimited) use or the right of lifetime inheritable possession. If there is a right of gratuitous use of the land plot or its lease, which by definition are characterized by a much less stable legal relationship with the taxpayer, then the object of this tax is absent (Cockfield: 2002).

It is obvious that the tax base is regarded as a cost, quantitative, or physical characteristic of the object of taxation, which is determined for each tax independently. One cannot but agree with the opinion of scientists that the tax base is one of the tools of the State's tax policy, and this, in turn, allows the regulatory function of the tax to be realized.

The main function of the tax base, as A.V. Demin considers, is to express the object of taxation quantitatively, i.e., measure it. For this, it is necessary to select a parameter that will be used as the basis for measuring the object of taxation. However, the tax base is not just a parameter. It is a parameter expressed in certain tax units, i.e. the tax base is the size (value) of the object of taxation in units of taxation. Since the tax base and the procedure for determining they are established for each tax separately, the task of the legislator is to select from the set of possible parameters of the object of taxation the most optimal and then determine the procedure for calculating the tax base in relation to a specific tax. It is rather often, such parameters coincide for different taxes, but the tax bases are always calculated differently (Babin & Vakaryuk: 2018).

Most often, in practice, a cost (money) parameter is used. The value (monetary) parameter has VAT. Physical parameters represent a variety of physical characteristics, including area, volume, power, mass, etc. Water and transport taxes are an example (Babin & Vakaryuk: 2018, pp. 21-40). Today, the definition of the tax base for personal property tax based on the cadastral value of real estate remains one of the topical issues.

It is also disputable to establish a date with which the cadastral value, revised according to the results of the contest, is valid. In accordance with Article 403 of the Tax Code, in the event of the change of the cadastral value of the property object, according to the decision of Commission on consideration of disputes on results of definition of cadastral cost or judgment of any court, a new information about the cadastral value is taken into account when determining the tax base, starting with the tax period in which the relevant application has been submitted. Given the fact that the taxpayer actually learns about the tax base and tax liability upon receipt of a tax notice (i.e., in the new fiscal period), this provision requires adjustments (Shestak & Volevodz: 2019). The tax base is determined with the help of the methods that include: direct, indirect, conditional, lump-sum. For example, to calculate the profit tax, a direct method is used, which means measuring the tax base based on objectively existing and documented indicators.

The process of levying taxes will be effective only when the tax base accurately characterizes and determines the object of taxation. At the same time, the dependence between financial indicators and tax liabilities should be taken into account. The reliability, completeness of the collected and processed by the tax authorities with the help of digital technologies will allow improving the applicable tax forms in future. In order to ensure this process, it is necessary to harmonize tax and accounting legislation. On the one hand, the methodological approach to calculating the tax base based on accounting data requires the formation of accounting data with a greater degree of objectivity. On the other hand, the tax legislation must take into account the specifics of the formation of accounting indicators when choosing the limitations and norms that determine the method of calculating the tax base. In conditions of development of digital economy it will allow ordering algorithms of data processing and access to such data.