Question

Customer Officer: May I have your declaration from, please?
.
.
Customer Officer : Sure. Please open your suitcase.

(Is the expression 'suitcase' correct in this situation? Do you have some other suitable expressions? Correct the errors, plese.)

Answer 1

In your first sentence, the word needs to be "form" not "from" -- this is a typo I make all the time, and I have to be very conscious of it since a spell-checker will never pick it up!

The use of the word "suitcase" is correct. You could also use "briefcase" or "attache" or "valise" or "bag."

Answer 2

In the United States, the term, "Customs Officer," is more likely to be used.