Yes there is a big difference, in italian there are singular and plural persons. Io, tu and lui/lei are singular (in english they are I, you, he/she) Noi, voi and loro are the plural persons (we, you all, they) so for a grup of people youmwould have tomsay "Voi bevete" ( You all drink, or, You guys drink)
Scriviamo = We write
Scrivi = You write (informal)
Scriviono = They write.
Scrivete = You write. (Plural, this is like you all or y'all in English.)