USPS Exam 421 Window Clerk Study Guide Solutions (2025/2026) – Complete Practice Material with Verified Answers

USPS Exam 421 Window Clerk Study Guide
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90 Original Questions • Fully Solved • Exam-Ready Practice
Question 1:

A customer at the retail window wants to send a 1.5-ounce birthday card with a wax seal. Which
USPS mail class is the most cost-effective choice that includes forwarding and return service?

A. First-Class Mail

B. Priority Mail

C. Ground Advantage

D. Media Mail

Correct Answer: A. First-Class Mail

Rationale: First-Class Mail (2025 rate) accommodates letters up to 3.5 oz and automatically
includes forwarding/return service—no extra fee for those features.

Question 2:

A Window Clerk receives a parcel bearing a handwritten label with the ZIP Code “10036-1234.”
The clerk should:

A. Reject the item for illegible ZIP

B. Accept it; ZIP+4 is valid

C. Remove the plus-four digits

D. Charge an addressing surcharge

Correct Answer: B. Accept it; ZIP+4 is valid

Rationale: ZIP+4 format is USPS-preferred; handwritten labels are acceptable if legible and
complete.

Question 3:

A retail customer ships a 2-lb boxed Bluetooth speaker to an APO/FPO (ZIP 09350). Which
domestic product can be used?

,A. Ground Advantage

B. Priority Mail

C. Media Mail

D. First-Class Package International

Correct Answer: B. Priority Mail

Rationale: Priority Mail (domestic) serves all APO/FPO ZIPs including AE/AA/AP; Ground
Advantage excludes APO/FPO parcels over 15.999 oz.

Question 4:

While processing a return, the POS displays “USPS Money Order 12345678 – STALE DATED.” The
clerk must:

A. Refuse the money order completely

B. Accept it as regular mail

C. Issue a replacement after customer completes PS Form 6401

D. Cash it and deduct a 10 % fee

Correct Answer: C. Issue a replacement after customer completes PS Form 6401

Rationale: Stale-dated money orders (>1 year) are replaced, not cashed, via PS 6401 inquiry
process.

Question 5:

A deaf customer hands the clerk a written note requesting a PO Box. The clerk should:

A. Direct the customer to an online-only application

B. Provide Form 1093 and communicate in writing

C. Call a sign-language interpreter immediately

D. Ask a coworker to “speak louder”

Correct Answer: B. Provide Form 1093 and communicate in writing

Rationale: Written exchange respects communication preference; no interpreter is required for
simple written tasks.

Question 6:

, A customer ships a 0.9-ounce keychain in a 6" × 9" poly-mailer domestically. Which retail
product is cheapest in 2025?

A. First-Class Package Service—Commercial

B. Ground Advantage Retail

C. First-Class Mail Large Envelope

D. Priority Mail Flat-Rate Envelope

Correct Answer: C. First-Class Mail Large Envelope

Rationale: Under 1 oz and within large-envelope dimensions (≤¾" thick) qualifies for the lowest
First-Class Mail retail rate; packages >¾" incur package pricing.

Question 7:

Window policy requires balancing the POS cash drawer. How often must this occur?

A. At the beginning of every shift

B. Once per calendar day

C. Only when the supervisor is present

D. Only if cash exceeds $500

Correct Answer: A. At the beginning of every shift

Rationale: USPS Handbook F-101 mandates start-of-shift balance to establish accountability and
detect overnight discrepancies.

Question 8:

A customer presents a passport card as ID for a Signature Confirmation purchase. The clerk
must:

A. Reject it—only passport books are accepted

B. Accept it—passport card is valid federal ID

C. Request secondary ID

D. Photocopy the card for retention

Correct Answer: B. Accept it—passport card is valid federal ID