1) Le diste a José ese anillo de allí.
2) Le escribimos algunas veces.
3) Te compre este collar.
4) Nos han comprado mamá y papá estos souvenirs en Barcelona.
I am not completely sure about #4 I don’t think there is a word in Spanish for souvenirs but that might be only in my country.
Yes you may write a letter to your pen pal in costa rica
they teach to how they are before, they teach their costums, costumbres and more