Let me preface this: I am not a tax lawyer, I pay someone to do my taxes, and I find the tax code confusing. If you need tax filing advice, consult a tax person, not someone who hates tax law.
Here is what I do know about the tax code. If you were married on December 31, 2020, you have to either file married filing jointly or married filing separately. That changes your standard deduction. If you withheld as married in 2020, it might really reduce your refund or cause you to owe if you file married filing separately.
If you are planning on getting divorced this year, it might make sense to review your withholdings for 2021 so you do not owe in 2022. I use free tax estimators for myself, and they are accurate enough. There is a form your employer uses called a W-4 to help you figure out how much to withhold.
As a part of your divorce, if you have children, you have to decide how those deductions are divided too. Sometimes it makes sense for one person to have all of them, and sometimes it makes sense for deductions to be shared.
This is not a topic I have seen included on any of the paid forms out there I am not sure if it is on the standard parenting plan that the state provides for free. But, it is something I will put in my parenting plans. because I think it is part of the child support questions. In other words, a professionally done parenting plan thinks of questions like that and makes sure it is included.
If you have tax questions, hire a tax professional. If you want an attorney to make sure your tax deductions are done right in your parenting plan, reach out to my office.