[yyhhsj0521]

I had to file my tax by postal mail in the US. Granted there is the option to file online, but that only works for ~80% of the people when things are completely within the intended domain. I have just one extra item outside of standard salary slips and some investment income, so I had to file physically.

[ndiddy]

For federal returns, there's a site called Free File Fillable Forms, which has digitized versions of all the tax forms. Unlike the normal IRS Free File program, there's no restriction on income. If you're comfortable filing paper tax returns, this is the exact same process except the returns are digital and sent over the internet. For state returns, the process depends on your state but everywhere I've lived has a free site that you can use to file your state return.

[dpifke]

From https://www.irs.gov/e-file-providers/free-file-fillable-form...:

Attaching statements — This program does not allow you to attach any documents to your return, except those available through the program. If you need to attach any such documents, you will have to print and mail in the return.

Especially with business returns, it's common to have to attach statements to certain forms, for example if you choose the de minimis election for equipment repairs that would otherwise have to be capitalized, or when the § 174 changes went into effect and everyone had to start amortizing software development expenses over multiple years. You can't do that on Free File Fillable Forms.