Names, Date of birth, and Social Security numbers of yourself, spouse, and all dependents.
All Income documents (W-2’s, 1099’s, Self-employed earnings). Other documents vary depending on individual tax situation (homeowner, married, children, Student loan, investments, Self-employed, Retired…)
You may file your taxes once you have received all your W-2(s) from your employer(s). Employers are required to submit and mail all tax-related documents by January 31, so if you have received all tax documents, you are ready to file.