llamar is a regular -ar verb, meaning to call (summon, name, etc.)

See -ar verbs.

Notably:

• The reflexive form (llamarse) is used for personal naming (me llamo Miguel)

• Intransitive (no object) is used for calling (telephone), knocking at the door, etc.
  ¿Quién llama? – who’s there? (who knocks/calls?)

• Transitive only takes a direct object (in general), it seems:
  Juan llamó a María – Juan called (after) María; Juan la llamó – Juan called (after) her.

  The latter, with most verbs, would use an indirect object form:
  Juan no contestó a María – Juan did not answer María; Juan no le contestó – Juan did not answer her.