I assume you mean "Inga, inget, och ingen." They're all the same word with minor changes, and they all mean "no." For example, if you say, "I have no shoes," because the word "no" is describing is plural (shoes), you would say "inga," because inga is used when the thing it describes is plural. Therefore, "Jag har inga skor," would be correct. If you want to say, "I have no food," because "food" is an en word and in the singular, you would use ingen. What you would say, then, is "Jag har ingen mat." Likewise, if what "inga/ingen/inget" describes is a singular ett word, you would use inget. "I have no child." Because child, in Swedish, is an ett word, you would say, "Jag har inget barn." And inga is used if its plural. It doesn't matter if it is an en or ett word.