I assume you mean that the bonus is on a 1099-MISC. (There is no plain Form 1099. There are 20 different kinds of 1099 forms. They all have one or more letters after the 1099, such as 1099-G, 1099-INT, 1099-MISC, etc.)
The employer that gave you the 1099-MISC is reporting the bonus incorrectly. All payments from an employer to an employee should be treated as wages and included in the employee's W-2. It doesn't matter whether it's regular pay or a bonus. However, there is a way to report the bonus correctly on your tax return, in spite of your employer's error.
I assume that your employer reported the bonus in box 7 of the Form 1099-MISC, and that you also received a Form W-2 for 2018 from the same employer.
Follow the steps below to enter the 1099-MISC in TurboTax. The bonus will be included in the total wages on Form 1040 line 1. On the dotted line to the left of the amount on line 1 there will be a notation "F8919" and the amount of the bonus. Form 8919 will be included in the return, with reason code H in column (c). Form 8919 will calculate the Social Security and Medicare taxes that your employer should have withheld from the bonus. The total of these taxes will appear on Schedule 4 line 58 and will be included in your total tax liability.
- Click the Federal Taxes tab. (In TurboTax Self-Employed or Home & Business click the Personal Tab.)
- Click Wages & Income. (In TurboTax Self-Employed or Home & Business click Personal Income.)
- Click "I'll choose what I work on" or "Jump to a full list."
- On the screen "Your 2018 Income Summary," scroll all the way down to the last section "Less Common Income." Click the Start button for the last topic, "Miscellaneous Income, 1099-A, 1099-C."
- On the next screen click the Start button for "Other income not already reported on a Form W-2 or Form 1099."
- The next screen asks "Did you receive any other wages?" Select Yes and click Continue.
- The next two screens ask about household employee wages and sick or disability pay. Click Continue on these two screens without entering anything.
- The next screen asks "Did you earn any other wages?" Select Yes and click Continue.
- The next screen asks the source of the other earned income. Select "Employee compensation that was not reported on a W-2." Ignore the note that says not to enter compensation for which you will receive a 1099. Click Continue.
- On the next screen, "Employee Compensation Not Reported on a W-2," click Continue.
- If you are filing a joint return, you will get a screen asking which one of you the income is for. Select your name and click Continue.
- On the next screen, "Report Your Wage Income," enter the employer's name and EIN from your W-2. When entering the EIN, you must enter the hyphen after the first two digits. For Total Wages Received, enter the amount on the 1099-MISC. Select Reason Code H. Click Continue.
- On the next screen, "Report as Wages," click Done.
- This returns you to the Miscellaneous Income screen. Click Continue.
