Interrogatives + じょし


In cases like 何でも and 何も, are they considered words on their own, or are they
considered words + じょし? I've been told that it's one word, but sometimes the
particle is separated like in: どこへもいきません。If it is a word plus a particle, why
are the particles でも, か, and も used, what do they mean, and how do they change
the interrogative? Also, how would I say "I want to go everywhere" in
Japanese? I was told that どこも行きたい is incorrect, but I don't know how else to
phrase it. Doesn't どこも mean "nowhere" when the verb is negative, and
"everywhere" when the verb is positive?




Generally, monolingual dictionaries consider 何でも, 誰でも, いつでも, どこでも and such as
two words, i.e., an interrogative 何/etc followed by the particle でも. (They
have an entry for 何でも anyway because 何でも has a significant meaning as a set
phrase.) 誰にも, どこからでも and so on are three words (だれ + に + も = "to anyone", どこ +
から + でも = "from anywhere").

Dictionaries for Japanese learners may list them as one word for the sake of
convenience. There is [more than one way to separate
words](https://japanese.stackexchange.com/q/36310/5010), after all.

"I want to go everywhere" is どこ **へでも** 行きたい or どこ **にでも** 行きたい. You need a
destination marker へ or に. You have to use でも instead of も if your sentence is
non-negative. For details, see:
[「どこでもある」と「どこにもある」の使い分け](https://japanese.stackexchange.com/q/17697/5010)

