* "vir" - This is the most common way to say "come" in Portuguese, meaning "to come" in general.
* "vem" - This is the informal, second-person singular (you) imperative form of "vir," meaning "come" (here).
Here are some examples:
* "Eu quero vir para cá." (I want to come here.)
* "Vem cá!" (Come here!)
The spelling you choose depends on the context and the grammatical structure of your sentence.