Indicativo
Indicative mood · facts and certainty
The mood of facts. It states what is, was, or will be, and presents it as real or certain. The Real Academia counts the Condicional as one of its tenses.
8 tenses
The four moods
A mood is what a sentence does with a fact: states it, wishes it, supposes it, or demands it.
Subjuntivo
Subjunctive mood · wishes, doubt, emotion
The mood of wishes, doubt, emotion, and hypotheticals. It usually follows que or a trigger such as ojalá or para que, and appears in si-clauses about unlikely or unreal situations. Compare the indicative, which states facts.
6 tenses
Condicional
Conditional mood · what would happen
What would happen under a condition, plus polite requests. Most textbooks treat it as its own mood; the Real Academia counts it as a tense of the indicative, where it is called pospretérito.
2 tenses
Imperativo
Imperative mood · commands
Commands, requests, and invitations. It has no past or future, and only tú and vosotros have affirmative forms of their own; the rest borrow the Presente de subjuntivo.
1 tenses