t means you don't have to file your tax return.
Not everyone is
required to file a tax return. If your income is lower than a certain
dollar amount (set by the IRS), the IRS allows you NOT to file your tax
return- you are considered by the IRS to be below filing requirements.
Below link provides that set amount, which indicates if you need to file or not:
https://ttlc.intuit.com/replies/3302274