Do I need to submit any papers in court that I am moving to a different state with the child?

I have sole legal, sole physical, sole primary custody, I live with the child. My ex has visitation rights. Ex sees child once a month and ex lives in another state. I got a great job in different state. I do not want my ex to lose visitations once a month and even willing to pay flight tickets for our child to come and see the parent. How this works? I can just move away with the child and my ex can continue see the child once a month.