If I made less than $600 selling digital materials online and did not get a 1099, how do I report this and where?

It sounds like you have a home business

• You must file a return if your net profit is over $400.
• You must then pay self-employment tax if you had net earnings from self-employment of $400 or more.
•  Generally, the amount subject to self-employment tax is 92.35% of your net earnings from self-employment.

Self-employment tax