You could omit 'I would like to inform you that'.

What do the 8 numbers in brackets refer to?

I would like to inform you that I have added 78 new books (100,200,300,500,600, 700,800,900) to our stock loan section. Please see the attached file for the book list. If you want to borrow one of them that book you can come and take it  before they are gone. They Books are available near the counter.

Do you need to say this?

If you want to borrow one of them that book you can come and take it  before they are gone.

Surely it's obvious that this is what you do in a loan section. You don't need to tell people.

Best wishes, Clive