Grammar

Hi, Jasvinder. Thanks for joining us. Welcome to English Forums. [<:o)]

Your sentence is correct.

We assume that some prior context makes the past perfect tense appropriate.

However, if the simple past will do the job, that would be a better choice.
(I sent one resume.)

Best wishes, - A.

thanks a lot...English forums is so quick..Now i can learn english at a pace...

I thought perhaps I should give an example of "prior context," but you were too quick for me!

I didn't understand why the HR Director thought I was being too pushy. I had sent one resume.

Your choice of tense emphasizes that the sending occurred before the misunderstanding.