How much is tax in Spain for foreigners?

Could you please clarify for me the tax rates in Spain for foreigners? I'm interested in understanding the specifics of the tax system for non-residents. Are there any special considerations or exemptions that might apply to foreigners? Also, do the tax rates vary depending on the type of income, such as employment income, investment income, or capital gains? I'd appreciate it if you could provide a brief overview of the taxation process for foreigners in Spain. Thank you for your assistance in this matter.