"Usted is the formal singular second-person subject pronoun, while "ustedes" is the formal plural second-person subject pronoun.
The affirmative formal commands are the same as the present subjunctive form. The endings for verbs that end on "-ar" are "e" for "usted", and "en" for "ustedes". The endings for verbs that end on "-er" or "-ir" are "a" for "usted", and "an" for "ustedes".
