You are reporting self-employment income on Schedule C. The Schedule C reports gross sales revenue with a one line entry Other self-employed income, includes cash and checks such as here.
The one line entry is sufficient provided that the entry reports at least $6,331. The Schedule C may report the cost of sales and positive Schedule C income will be subject to income tax as well as self-employment tax.
You may also report two lines of income, one line in the amount of $6,331 and the second line in the amount of the remaining income reported on your Schedule C.
For instance, if you Schedule C reports gross income of $12,331, you may report two lines, one for $6,000 and one for $6,331.
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