The general format is good, but there are some errors:
Positioning of the return address: It was written based off of the right margin. You should set a tab just to the right of the mid-point of the page and write it from there.
Positioning of the closing and signature are off. They should always be aligned with the return address whether using block-left format or modified block-left format.
Format of the return address: there are positioning errors in the position of some information elements.
Inside address lacks a company name. It would also be good if you could contact the company and get a specific person’s name and title to address the letter to. It looks more professional and shows good initiative and drive by the applicant.