Why would I owe taxes? I’m just confused, I didn’t owe last year, I don’t know why I owe this year. When I estimate and do my W-2’s separately I get a return from both but when I do then together it says I owe, why’s that? I had a 0 on my form but recently changed it to a 1 since I do my own taxes. Do I have to file taxes?

I’m not really educated on this stuff and yes I did already look it up on Google and it said too little was withheld which doesn’t make sense to me