“Was” and “were” are both simple past tense forms of the stative verb “be.” The correct form to use depends on the subject.
“Was” is used for most singular subjects, including first person and third person (e.g., “I was,” “she was”).
“Were” is used for plural subjects (e.g., “we were,” “they were”), but it’s also used for the second person regardless of whether the subject is singular or plural (e.g., “you were”).
Whether “was” or “were” is correct can also depend on whether you’re using the subjunctive mood or indicative mood. The subjunctive mood is used to express wishes, hypotheticals, and suggestions (e.g., “if I were you, I would say something”).
QuillBot’s Grammar Checker can help you ensure you’re using was and were correctly.