Template:Sic/doc

Description
"Used in brackets after a copied or quoted word that appears odd or erroneous to show that the word is quoted exactly as it stands in the original, as in a story must hold a child's interest and “enrich his [ sic ] life.”."

- Google

Basically, if something contains a grammatical error on purpose, stick  next to the word or sentence to indicate that it shouldn't be "fixed."

Examples
I realy h8 peopel [sic] Oops, I droped [sic] something! Waht [sic] are you doing? I told yu [sic] NOT to do that!