There are two main types of verbs: transitive and intransitive verbs. However, some intransitive verbs can also be described as linking verbs.
Transitive verbs take a direct object. The word transitive is derived from the Latin verb transire, which means to go or cross over. English actually has quite a few words that start with trans, and in each case the prefix means across / cross:
translate = carry across (from one language to another)
transvestite = cross dresser
transition = crossing over
transport = convey across
trans-Atlantic = across the Atlantic
In the same way, transitive verbs carry the action across to a direct object:
She sold her car.
Transitive verb: sold.
Direct object: her car.
By contrast, intransitive verbs lack a direct object:
I fell down the stairs.
Intransitive verb: fell.
Prepositional phrase: down the stairs.
If we asked fell what? there is no answer. The prepositional phrase explains where these actions took place, but there is no direct object.
However, there are many verbs that can be both transitive and intransitive:
I guessed the answer.
I just guessed.
In most dictionaries, the abbreviations vt and vi will tell you if a verb is transitive, intransitive, or both.