If you have a letter that needs a diacritical mark, hold the key down longer than usual and a pop-up menu will appear. Simply click on the correct symbol and it will insert itself in what you're typing.
For example when typing the letter "u" hold do the the "u" longer and you will have the option of different special characters.
Another Way to Type Accented Letters on a Mac The trick is to type a modified letter (e.g. é, ü, or ñ), you type a special key combination followed by the letter. Here's how, to type vowels with an acute accent on them (namely the á, é, í, ó, and ú), press the Option key and the "e" key at the same time, and then release the keys. This tells your computer that the next letter will have the acute accent. To type á, press and hold the Option key, then press the "e" key, now release both the Option and "e", now type the "a." Now you will have typed á. If you want it capitalized, the process is the same, except press the "a" and the shift key at the same time, as you would normally for a capital "a." The process is similar for other special letters. To type the ñ, press the Option and "n" keys and release them, then press the "n." To type the ü, press the Option and "u" keys release them, then press the "u." Here is a list of special letters and the key commands:
á — Option + e, a
Á — Option + e, Shift + a
é — Option + e, e
É — Option + e, Shift + e
í — Option + e, i
Í — Option + e, Shift + i
ñ — Option + n, n
Ñ — Option + n, Shift + n
ó — Option + e, o
Ó — Option + e, Shift + o
ú — Option + e, u
Ú — Option + e, Shift + u
ü — Option + u, u
Ü — Option + u, Shift + u
Typing Spanish Punctuation on a Mac To type Spanish punctuation, it is necessary to press two or three keys at the same time. Here are the combinations to learn:
inverted question mark (¿) — Shift + Option + ?
inverted exclamation point (¡) — Option + 1
left angle quote («) — Option + \
right angle quote (») — Shift + Option + \
quotation dash (—) — Shift + Option + -