On Windows

The numbers are type on the numerical keyboard.
 
á
press ALT and type 160 or 0225
é
press ALT and type130 or 0233
í
press ALT and type161 or 0237
ó
press ALT and type162 or 0243
ú
press ALT and type163 or 0250
Á
press ALT and type 0193
É
press ALT and type 0201
Í
press ALT and type 0205
Ó
press ALT and type 0211
Ú
press ALT and type 0218
ü
press ALT and type129 or 0252
Ü
press ALT and type154 or 0220
ñ
press ALT and type164 or 0241
Ñ
press ALT and type165 or 0209
¿
press ALT and type168 or 0191
¡
press ALT and type173 or 0161
¼
press ALT and type172
½
press ALT and type171
º
press ALT and type167

 

On Macintosh

To capitalise, also press Shift.

á press Option and e release and type a
é press Option and e release and type e
í press Option and e release and type i
ó press Option and e release and type o
ú press Option and e release and type u
Á press Option, e and Shift release and type a
É press Option, e and Shift release and type e
Í press Option, e and Shift release and type i
Ó press Option, e and Shift release and type o
Ú press Option, e and Shift release and type u
ü press Option and e release and type u
Ü press Option and u release and type u
ñ press Option and n release and type n
Ñ press Option, n and Shift release and type n
¿ press Option and Shift and type /
¡ press Option and type 1