In my poetry I want to have imaginative freedom. What is this?
There should be no no arbitrary restrictions in place. Those are rules that are simply conventions of the genre, as might be practiced in one particular place or time, but that aren't really "rules." Or they are prejudices that many people might share at any given time. Take rhyme. If you are imaginatively free then you can rhyme or not rhyme. It doesn't make any difference. You can choose, imaginatively, to impose constraints on your writing, but that will be a free choice as well.
You give yourself permission to do what you want. So if you think you can't be confessional, or sentimental, or prosaic, you have to realize that that restriction comes from you, not anyone else. You are the one denying permission to yourself, even if it seems like it's someone else.
You really shouldn't have a style. That is to say, you shouldn't have to decide what your poetry is like and then impose that as a restriction. (You can for individual poems or books, but that is another question.). Of course, it will sound like you anyway even if you try to avoid your stylistic tics. Very few poets have the freedom to do whatever they really might want. But at least in theory you can leave yourself open to any possibility.
The problem is that poets learn enough licks to be able to write ok, and then they stop. They have enough tools and clichés and can have their work considered good. There was on in the 70s I remember: poets would write the line "for hours" or "for years," which had a certain built-in poignancy. Like: "I washed the dishes / for years." Or they would use certain words like silence, dark, and stone that they thought had an inherently lyrical quality.
The bad poetry I was writing since the summer, I realize now, is just the key to the gate of imaginative freedom. Because if you do something in a bad poem, and it works, then you've found something that works.
At the same time, you have to have some self-awareness not to write something bad and not even know that it's bad. There was a bad Chilean poet who had a foundation set up for him that will essentially pay people to translate or write about his work. I thought it would be easy money so I checked his books out of the library one year, but it was crappy stuff, and I couldn't bring myself to translate it. It was over-clever and without redeeming social value. The fact they needed to pay people to even approach it is fairly appropriate.
This is a life hack not just a poetry hack because it is applicable to other situations in which you might need imaginative freedom to free up your life. Say to yourself: I cannot imagine not >>>>> Then imagine not doing it.