Rented out or for your own use
How the two situations differ for your filing.
Whether your Spanish property is rented out or kept for your own use changes what your Modelo 210 looks like.
For a property you keep for your own use, there is no rent to report. Spain calculates a small amount of deemed income from the property's rateable value (the valor catastral), and that return is filed once a year, by 31 December of the following year.
If you rent the property out, you declare the rent you receive instead. The timing and detail differ from the own-use case, so your gestor confirms exactly what applies to you before anything is filed.
File this year's Modelo 210 without the stress
Start in your language. You'll see the price before anything is filed.