Form 1040 is the U.S. Individual Income Tax Return form, and it is required to be filed by individuals who meet specific criteria. Generally, individuals in the following situations are required to file Form 1040: 1. Single individuals with income of at least $12,400 ($24,800 for married couples filing jointly) in 2020. 2. Individuals who are married filing separately with income of at least $5. 3. Individuals who are self-employed and have net earnings of $400 or more. 4. Individuals who owe taxes because of retirement plans, recapture taxes, alternative minimum tax, household employment taxes, or other situations. 5. Individuals who received more than $400 in income as a church employee subject to the mandatory Social Security and Medicare taxes. Note that the filing requirements may vary based on factors such as age, filing status, and type of income. It is always recommended to review the instructions provided by the Internal Revenue Service (IRS) or consult a tax professional to determine your specific filing requirements.