The filing requirements for a federal tax return depend on factors such as the taxpayer's income, the taxpayer's age and filing status, the age of the spouse on joint returns, if the taxpayer is claimed as a dependent on someone else's return, earnings from self-employment, and more.
The IRS Interactive Tax Assistant (ITA) topic Do I need to file a tax return? can walk you through steps to determine your filing requirements.
To determine the requirements for your situation on your own, please refer to the IRS Instructions for Form 1040 and review the following charts (Tip: type CTRL+F to search the instructions):
You can also refer to IRS Publication 501 Exemptions, Standard Deduction, and Filing Information.