'They got married' is past simple. 'They have got married' is present perfect. (This is British English. American English would be 'gotten married'. But it's just two different participles - the tense is the same.) So the difference is the difference between those two tenses. Is this your actual question? Are you confused about the difference between past simple and present perfect in general?

Actually, “to get married” is an expression using the passive voice with “get” instead of “to be”, so “married” is the passive participle. The difference between “they got” and “they have gotten” is the usual, as Claire has explained. For example, if Michael and Michelle got married, the actor was actually the judge (captain of the ship, priest, etc.) who married Michael and Michelle (or married one to the other). Usually we're interested in the couple more than the judge, so we use the passive: Michelle and Michael got married (by the judge, etc.). Michelle got married to Michael. They are now married (to each other). Note: Do not use the preposition “with” to talk about who is married to whom.

Hi Viola, it should be "got married" or "have gotten married". The difference is that they are different tenses (past simple and present perfect). Hope this helps :)

Got married refers to married or not. Have Got married refers to a recent marriage.

"Married" in these partial sentences is a "predicate adjective". A predicate adjective modifies the subject of the sentence. Your sentences lack a subject, but if you had put one there, married would modify the subject. For example, in "I got married", "married" modifies "I". Predicate adjectives follow "linking verbs". Here are more examples: The hat looks big. He got sick. She's feeling good. They seem married.