Request For Verification Of Employment Employment Verification?

Employment verification? - request for verification of employment

I have my old job 3 months ago. Can someone help me write a letter asking for verification of employment from my former employer?
I worked for 4 ½ years, and my boss was a little awkward to my departure, because of all the work for a very long time. The state of the same company for 25 years. Both sales within 10 to 15 years. Production Manager: 20 years. Send and Receive: 19
I need help writing the letter more formal and polite. Please help. Thank you!