"schedule C worksheet: amount - misc exp qsbe" is a worksheet in the TurboTax application that reports Miscellaneous Expenses for a Qualified Small Business Entity, in other words, the expenses you entered for the business under the category "Miscellaneous"
Schedule C is reported and included as part of your tax return when you are Self-Employed, or also known as having a "Sole-Proprietorship".
When a person works as a "gig" worker, like DoorDash, they are not working as an employee, they are self-employed. That means that they need to report their income, expenses and most important, pay their own FICA tax. FICA tax is Medicare and Social Security Payments that an employer usually withholds from Employee pay and sends in for the employee. When you work as a self-employed worker, you need to make those payments yourself, by way of your tax return.