A Social Security number (SSN) is given to temporary working residents for taxation purposes. All people working in the U.S. must have one and file taxes.
Your SSN card will be mailed to you in about 2-3 weeks. It takes longer if:
Necessary documents vary depending if you request a REAL ID-compliant driver license or a Non REAL ID-compliant driver license. The differences and necessary documentation can be found on the Missouri Department of Revenue website.