If you are filing a Schedule C for self employment or as a Single Member LLC or Sole Proprietor, etc. you cannot take a withdrawal or salary and include it as an expense on your tax return. You are not an employee of the business. You don't pay yourself or enter a salary or withdrawal for yourself. All the business income and expenses are your personal income and expenses in the first place. You just fill out a Schedule C. The net profit or loss is your income. If you have a net profit of $400 or more on schedule C you will pay SE self employment tax on it in addition to your regular income tax. It's all included on your personal 1040 form.
You don't enter your pay or withdrawals on schedule C or into your tax return at all. And you don’t include it as income anywhere else. (And if you paid yourself and deducted it as an expense then you would have to include it as income on the same tax return so it would be a wash.)
See Schedule C instructions page C-10 Line 26
Do not include salaries and wages deducted elsewhere on your return or
amounts paid to yourself.
https://www.irs.gov/pub/irs-pdf/i1040sc.pdf
