I dropped off my friend at home. -- You took your friend to his house. (Use drop if you want present tense) I dropped in on my friend at home. -- You visited your friend at his house without telling him first.
Aside from the other answers, your question mark (?) should be at the end of your actual question. You should also get out of the habit of writing for the internet or texts. Sentences and the word "I" always start with a capital letter. Your use of "it" in the question does not automatically refer back to your previous sentence. It is understandable, but causes the reader/hearer to hesitate while