Help i keep getting a line from where i made a mirror modifier

Im currently learning how to use the mirror modifier and every time i set it up and work on a model ,there’s like a line seperating the mirror half from the other half so i have like finished models with a straight line going threw them…help anyone

That’s basically how it works. You mirrored an object and the line will show up along the axis of the mirror. This should not affect things very much though.