I have seen a lot of posts recently where someone stated “I seen”. Seen is a past participle and needs to be used with other verbs. For example, I have seen, I had seen, or I was seen. If you do not wish to get so technical, you can use saw which is the past tense of see. Example; I saw a man.
It might seem like such a small thing and if you don’t care that’s fine. It just doesn’t look like they are teaching grammar in school anymore and I thought that I would help out for anyone who might have wanted some help.