The pronoun in the contraction they've is they, the third person, plural, subjective, personal pronoun. The contraction they've is a combination of the subject pronoun they with the verb have. Examples:
They have gone on vacation. Or, They've gone on vacation.
They have not had their lunch yet. Or, They've not had their lunch yet.
yes theyve kissed
yes theyve both confirmed it
They go home.
Nah theyve just got bare attitude!
They had festivals to celebrate their work theyve dieb
He is scared about where theyve been
Noo theyve always had Jacoby Shaddix
its becasue he doesnt know where theyve been
get seeds plant them in a warm place. when theyve grown, eat them
theyve been around since 1776
Of course you can but it's not going to grow back!
yes theyve always been in colour