Source: IRS.gov: https://www.irs.gov/newsroom/nine-common-filing-errors-to-avoid

Errors can slow down the processing of your return and potentially delay your refund. So, before you hit send or seal the envelope to file your 2019 tax return, make sure your return is IRS-ready. According to the IRS, these are some of the common errors people make when filing their tax returns.

Social Security number errors
Did you remember to include your Social Security number on your return, and does it match the information on your Social Security card? Missing or incorrect numbers are common issues on many taxpayers’ returns.

Incorrect or misspelled names
If you have a nickname, don’t make the mistake of putting it on your tax return. The name on your return must match the name on your Social Security card exactly.

Wrong filing status
If your marital status changed last year, you adopted a child or experienced another change that might impact your filing status, you may be confused about which filing status to select. IRS.gov offers a tool called the Interactive Tax Assistant to help you determine which status to choose.

Math errors
Check your work, then check it again. Math mistakes are easy to make, particularly on some of the more complex sections of your return, such as calculating the taxable portion of a pension, IRA distribution or Social Security benefits.

Credits and deduction errors
Do you take the standard deduction or itemize? Do you qualify for an Earned Income Tax Credit or have dependents? If you’re eligible for tax credits or deductions, make sure you’re entering the correct information that applies to your situation. Your tax professional can help. The IRS.gov Interactive Tax Assistant can help with these determinations as well.

Wrong bank account numbers
If you’re owed a refund, providing your bank information to the IRS typically means you’ll get it sooner than if you request a check. However, if you enter the wrong routing number or account number, your refund could be delayed.

No signature
Your tax return isn’t complete until you sign it. If you’re filing a joint return, both you and your spouse must sign. Filing electronically allows you to sign digitally and helps ensure you don’t skip this important step.

Wrong e-file PIN
If you’re filing electronically, your PIN is a number you selected when filing last year’s return. If you don’t remember your PIN, you can validate your return by entering your Adjusted Gross Income from last year.

Expired Individual Tax Identification Number (ITIN)
ITINs are used by the IRS to process tax returns for people who don’t have or aren’t eligible to have Social Security numbers. Filing with an expired ITIN means you won’t receive any exemptions or credits when your return is processed, and if you are owed a refund, it may be withheld. How do you know if your ITIN is expired? The IRS will contact you by mail and provide renewal instructions.

The easiest way to avoid a lot of these mistakes? File electronically. While not foolproof, it can help prevent many of these errors.