Hello
Thanks for posting a question to the board.
You asked what the difference is between 'Appreciate' and 'Appreciated'.
In short, 'appreciate' is active voice, and 'appreciated' is passive voice. Active voice sentences are preferred as they tend to be warm and personal. Passive voice sentences tend to sound formal and official.
In this case it's always better to use the active form. But if you do so, make sure that you use a complete sentence, especially for business correspondence.
So you would say 'I would appreciate it if you could........'
If you do use the passive form, use this structure 'Your prompt would be appreciated.'
Hope this helps.
Workplace English Expert
Regards
Workplace English Training E-Magazine Team