How do you say "to" in Spanish?
"a" literally translates as "to"
Voy a la tienda -- I am going to the store.
In some contexts, the English translation of "to" is contained in the Spanish infinitive:
Quiero ir a la tienda -- I want to go to the store. (ir = to go)
Quiero comprar leche a la tienda -- I want to buy milk at the store (comprar = to buy) ("a" can also be translated as "at")
That question is difficult to answer in a few words. Click the link to check what the SpanishDict site says about To