I worked for someone whose main office is in Va but had a business in TX

Where your employer has its headquarters isn't actually relevant to your personal income tax return, or taxes (e.g., Virginia).  Where your employer operates its business isn't actually relevant to your personal income tax return, or taxes, either (e.g., Texas).

What is relevant to your personal income taxes is where you actually live (or are "domiciled" in the language of the tax code), and where you physically work.

Your home state has the (legal) right to tax your wage income wherever you work, even at an out-of-state location.  The state where you physically work also has that same right to tax.  But in neither case does it matter where your employer is located.  That could be another state; it could also be another country.  To you, the individual worker, that factor is irrelevant.

Thus, in your resident state, as well as in the state where you work, you would need to file a personal income tax return.  To the extent that two states tax the very same income, there is a mechanism called a "tax credit" that takes care of restoring fairness to such a situation of double-taxed income.

However, if you both live and work in a state that does not tax personal income at all, like Texas or Florida for example, then you're lucky because you don't have any state tax return(s) to file at all.

Of course, a federal income tax return is still required for the IRS; but in the case of someone working and living in Texas, for instance, there is no state tax or tax return due.  The fact that the company may be based out of Virginia is simply not material.

Hopefully that explanation makes sense, and thank you for asking this important question.