In the simple present tense, the stative verb “be” is used to describe temporary present situations (e.g., “I am tired”) and unchanging situations (e.g., “Laura is a doctor”). The form of the verb varies depending on the subject:
The first person singular uses “am” (e.g., “I am”)
The third person singular uses “is” (e.g., “he is”, “she is”, “it is”)
All other subjects use “are” (e.g., “you are”, “we are”, “they are”)