Used in affirmative sentences to mean 'every place' or 'any place'. Often followed by a positive predicate.
This town is beautiful everywhere.
Everywhere was crowded, so I couldn't sit down.
nowhere; nothing (with negative verb)
Used with a negative verb to mean 'nowhere' or 'nothing (in terms of place)'. The negative form is essential for this meaning.
I couldn't find my wallet anywhere.
I don't want to go anywhere today.
all over; everywhere; all over the place
Compound of どこ (where) + も (inclusive particle). The combination yields 'everywhere' in positive contexts and 'nowhere' in negative contexts.