The letter
Real estate tax is due each year and invoiced by the municipality per calendar year, up front. The amount of tax is dependable on the so called ''WOZ value'', which is also determined by the municipality.
For information about the WOZ value, please see this article of the Dutch government related to this subject.
Every municipality can decide for itself the amount of tax levied. This is usually decided on a year to year basis.
Example
The layout of the letter(s) may differ between municipalities, but overall, property owners who rented out their property may expect a letter that looks like the following example (from the The Hague municipality).

Green marks the established WOZ value of the property for the applicable tax year 'Belastingjaar'. In the example, the tax year is 2021 and the property is valued at an amount of 220.000,-- EUR.
Yellow marks the levied property tax for the tax year. In the provided example, we see the tax in 2021 is set at 0.0516% of the WOZ value, which equals an amount of 113,52 EUR.
Purple marks the levied sewerage taxes and is not dependable on the amount of sewerage taxes. This tax is paid based on the connection between the sewerage and the property in question. Unlike the provided example, it may well be the case that other municipalities levy these taxes seperatly, since they are not related to the WOZ value.
Red marks the amount which should be paid to the municipality.
Taxes for users or for owners?
A frequently asked question regarding this topic. The municipality levies both owners and users (tenants) of a residential property. This is differentiated as a so-called 'Eigenarendeel' and 'Gebruikersdeel', which means 'Owners part' and 'Users part'.
As stipulated by law and jurisprudence, as a property owner, you cannot calculate the levied owners taxes to the user(s) of the property (tenant(s)). However, it is of course possible to take into account these taxes when deciding on a proper renting price, and 'include' these foreseeable taxes in the advertised flat rate.
Common mistakes by the municipality
The mail regarding the property tax is sent to the address of the property, and not to the actual residing address of the property owner. Solution; contact the municipality (beforehand) to make sure the mail has been sent to the correct address.
It can occur that user taxes have been levied on the owner, while, in fact, the owner does not reside on the property in question. The image hereunder is an example of such a mistake, since the orange marks the taxes which should be levied on the user(s), and not the owner(s).

In this example, the taxes which are referred to by AFV are the so - called waste taxes levied by the municipality of The Hague which should be paid by the users. More information on this specific topic can be found here.
Solution; contact the municipality to inform them that you are not residing on the property and that the property is unoccupied or rented out. If they are unwilling to help you directly, you should submit for an objection and/or appeal.