Who has the power to tax?

The power of taxation, being an essential and inherent attribute of sovereignty, belongs, as a matter of right, to every independent government, and needs no express conferment by the people before it can be exercised. It is purely legislative and, thus, cannot be delegated to the executive and judicial branches of government without running afoul to the theory of separation of powers. It, however, can be delegated to municipal corporations, consistent with the principle that legislative powers may be delegated to local governments in respect of matters of local concern.[1] The authority of provinces, cities, and municipalities to create their own sources of revenue and to levy taxes, therefore, is not inherent and may be exercised only to the extent that such power might be delegated to them either by the basic law or by statute.[2][1] Pepsi-Cola Bottling Company of the Philippines, Inc. v. Municipality of Tanauan, Leyte, The Municipal Mayor, et al., No. L-31156, February 27, 1976.
[2] Manila Electric Company v. Province of Laguna, G.R. No. 131359, May 5, 1999.