Can you add lo (it) to the end of a word if you just want to say 'something it'?

Example:
Mangialo adesso!!

Also, how do you say she likes?
This is how I would like it formatted - Lei ____ piace

Question

Can you add lo (it) to the end of a word if you just want to say 'something it'?

Example: 
Mangialo adesso!!

Also, how do you say she likes? 
This is how I would like it formatted - Lei ____ piace

Answer

No, you can't do that always. Only when you use a transitive verb. For instance, you can "mangialo adesso (eat it now) but you can't say "corrilo adesso", since correre is not transitive, so this sentence has no sense.