What ¿ means
It announces a question before ? arrives.
Place ¿ where the question starts, even mid-sentence. In “Pero ¿vienes mañana?” (“But are you coming tomorrow?”), only “vienes mañana” is the question.
Where did ¿ come from?
The Spanish Academy introduced it in 1754. That orthography, from the body that sets Spanish spelling rules, added the opening mark for long questions; during the nineteenth century the rule spread to every direct question.
Standard Spanish punctuation, not decoration.
In standard Spanish, use ¿ and ? as a pair.
Don't confuse it with
3Questions people ask
1Why does ¿ show as a box on some devices?
Because that device's fonts have no glyph for it. The character is still correct and still copies correctly — the box is a missing glyph, not a broken character.
How to type ¿
¿\00BFCodes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.