Best way to display phone numbers from various countries?

1. How do you layout phone numbers?
2. How do you display a US number?

How do you layout phone numbers?

Landline phone numbers begin with the area code, then one digit for the operator code, then six digits for the primary telephone number. Format: (XXX Y ZZZZZZ) where: "xxx" denotes the area code. All area codes begin with the number 0.

How do you display a US number?

(800)555-1234 (no space after the area code) 800-555-1234. 800 555-1234.