I am using turbo tax 2023 for tax preparation, and I don't see business expenses area to enter the business expenses.

It sounds like you entered the 1099-K in the Personal Section

Wages & Income

Other Common Income

Income from Form 1099-K

 

Instead, enter it under "Self-Employment" income

You may need to delete (use the trash can) the entry for the 1099-K you already made

 

If you are using TurboTax desktop Home & Business, select the Business Tab first

• Next select Business Income and Expenses
• Set-up the business if needed, 
• (if you used TurboTax last year, the business details should have been brought over)
•  
• After the business is set-up, scroll down to Business Income and select START
• Select "1099-K Income" and START

 

If you are starting in a lower TurboTax Online Program, 

• select "Wages & Income" on the left side-bar
• Scroll down to Self-Employment
• Open that section and select START
•  
• You will again setup the business if it has not already been done
• You may be prompted to enter expenses first
• After expenses you can scroll down to Income
• Select "Form 1099-K" and CONTINUE

(if you need help deleting the 1099-K )

For TurboTax Desktop, switch to Forms (Upper right corner) 
To Delete a Form  using TurboTax Online:
Select Tax Tools on the left side-bar
Select Tools from that drop-down
Select “Delete a form” on the TOOLS CENTER screen
Select the form, schedule and/or worksheet you wish to remove 
 

https://ttlc.intuit.com/turbotax-support/en-us/help-article/import-export-data-files/enter-schedule-c/L5Fz3j5us_US_en_US?uid=lflpan19

Schedule C, Profit or Loss from Business would be used to report all activities related to your nail salon.  The link provided by ee-ea above shows you the steps of how to enter these expenses into TurboTax.  

Any business income can be offset by any applicable expenses directly related to the business.  Expenses would include items such as rent, supplies, equipment, utilities, as well as any other expenses incurred as part of running your business.  Please see this link for additional details on what could be included in your self-employment business.

 

In addition to the link previously provided, you may be subject to self-employment taxes.   Self-employment taxes are comprised of Social Security and Medicare taxes. These taxes are calculated based upon 92.35% of your overall net earnings from your business.  TurboTax will calculate the total amount of any self-employment taxes that are due based upon your input for the business.  

 

@Quanghtran1972