No, "a" is an article, not a verb at all.
Read carefully:
https://www.englishgrammar101.com/module-3/verbs/lesson-3/linking-verbs
Is (a) a linking verb? :)
2 answers
No. A is an article and used as an adjective.
Common linking verbs are
am, is, are, was, were, become, seem
Examples:
I AM Ms. Sue.
You ARE pretty.
They WERE late.
She SEEMS tired.
Common linking verbs are
am, is, are, was, were, become, seem
Examples:
I AM Ms. Sue.
You ARE pretty.
They WERE late.
She SEEMS tired.