You need to give more context 14:24 Jun 9, 2018
namely, it's far from obvious WHO is doing the "acknowledgment", and OF WHAT exactly.
it could be the sender of the letter "acknowledging" some information received from the recipient of this letter, or it could be asking the recipient to acknowledge something that is in the letter.
it could also mean that there is blank space left after "For acknowledgement" for the recipient to sign and "acknowledge" whatever is contained in the letter.
All these "nuances" could change the translation ...
More context? | 
peer agreement (net): +2