Dictionaries record usage. They don’t take submissions. Use the word, write the word, get other people to use the word, and it will end up in the dictionary.
What @pdworkin said, as it applies to “real” (i.e., “legitimate”) dictionaries. However, you can submit entries to the Urban Dictionary. And that has a chance of actually popularizing your word someday—at least among perusers of the Urban Dictionary.