The constitutional principles of Tax Law; they already have their recognition in the writings of Adam Smith, from whose work it follows:
1) Equality before Public Charges, this is the proportion that must exist between the taxes and the economic capacities of the taxpayer;
2) Certainty, insofar as taxes must be clear, plain and intelligible; therefore, this principle is related to legality, since a valid and mandatory system must be established for both parties to the legal-tax relationship;
3) The Comfort and Convenience, in the opportunity and mode of payment; and
4) The Economy, which was of paramount importance, since it is evident that taxation will produce effects on production and savings.
Ibaceta Medina, D., & Meza Encina, B. (2016). Legality in the imposition of taxes: a constitutional look. Revista De Derecho Público, (66), Págs. 163–200. https://doi.org/10.5354/rdpu.v0i66.41668