German hat not only three grammatical genders, but also four grammatical cases. The noun »Straße« is always female, but - as any noun - it can appear in any of those four cases. And the article, often together with a changed ending of the noun, depends on this grammatical case.
Nominative case (Wer? oder Was? - Who? or What?):
Die Straße ist lang. - The street is long.
Wer oder was ist lang? - Who or what is long?
Genitive case (Wessen? - Whose?):
Das ist der Belag der Straße. - This is the street's surface.
Wessen Belag ist das? - Whose surface is this?
Dative case (Wem? - To whom? or To what?):
Die Leute geben der Straße einen Namen. - People give the street a name. (i.e., People give a name to the street.)
Wem geben die Leute einen Namen? - To whom or to what do people give a name?
Accusative case (Wen? oder Was? - Who? or What?):
Ich sehe die Straße - I see the street.
Wen oder was sehe ich? - Who or what do I see?
English does not have four cases. Some experts say that the concept of cases doesn't work for English, some say English has two cases (nominative and genitive). But as you come from the English language, you have to learn what cases are and what they are good for.
German has four cases, Latin has six, Estonian has 14 and Hungarian has 31 cases.