Report your income and expenses with the information on the forms you received on Schedule C.
Sounds like you are letting "Google" confuse you. No one files more than one Form 1040. You will prepare a Form 1040 that includes ALL of your income--including any W-2 income (if any) and your self-employment income. If you have W-2's from more than one employer, all of your W-2's must be entered on the same tax return. If you have self-employment income from several clients, then it is possible for you to have more than one 1099NEC to enter. There are other kinds of 1099's -- like 1099R, 1099B, 1099INT, 1099DIV, etc etc.--so if you have any other kinds of 1099's (you might not have any other kinds) then all of your 1099's must also be entered on the same tax return.
When you have self-employment income, you have to prepare a Schedule C to enter your business expenses, such as mileage. And you have to pay self-employment tax for Social Security and Medicare.
If you have self-employment income for which you will pay self-employment tax for Social Security and Medicare, you will need to use online Premium software or any version of the desktop software download so that you can prepare a Schedule C for your business expenses.
https://ttlc.intuit.com/community/self-employed/help/what-is-the-self-employment-tax/00/25922