A W-2 reports wage income and tax withholding. A 1099-NEC reports non-employee compensation. This means compensation for doing work for someone when you are not an employee, but an independent contractor or self-employed. The difference is explained here.
https://www.irs.gov/taxtopics/tc762
If you are self-employed, you report your income on a schedule C and pay self-employment tax, you can also subtract your ordinary and necessary business expenses.
There are many other types of 1099s -- all 1099s report some kind of income that is presumed to be taxable. There is 1099-B, 1099-DIV, 1099-INT, 1099-R, 1099-MISC, 1099-K, 1099-SA, and maybe others.
