The difference is that she's and similar shortened forms are used in colloquial speech, but not in certain cases. In short, she/they is the most common way for a person to indicate that they go by she/her or they/them pronouns, likely with a preference for the former. According to grammar rules, it should be this is she, because is is a linking verb (a verb that connects the subject to more information about the subject), so it can't have an object (her), but it's.
Soaps She Knows Gh Recaps at Charles Dunaway blog
Taken from the free online dictionary:
4、安静了 梦想中属于我们的婚礼 安静了 这首歌，是周杰伦邀请she参观他的新公司时，当场写出来的。she《play》专辑里面的一首歌曲 《借口》 拼贴了周杰伦的许多歌名，周杰伦听.
