Julián,
First of all, I must clarify for semantics' sake that there is no such thing as a physical English keyboard. There are Australian keyboards, English Canadian keyboards, Irish keyboards, United Kingdom keyboards, and USA keyboards, but no English keyboard. Commercially available keyboard layouts are classified by region. (Custom keymaps are a 2nd category, as I once hired to create a Guaraní keymap as a subset of the physical Spanish ISO keyboard. On the other hand, iPhone keymaps are yet a 3rd category.)
Having said that, I imagine that you have an Apple USA keyboard. To type the ¿ on the Apple USA keyboard in MacOS, you press SHIFT + ALT + ? simultaneously. To type the ¡ (inverted exclamation mark) key on the USA keyboard, you press ALT + 1 simultaneously. If for some reason your keyboard is Australian, Canadian, Irish, or UK, let me know, and I'll give you the appropriate combinations.