That certainly is the question so many poets toy with when they first begin to write poetry. They have the words inside that want to come out, but they're not sure of the best way to go with their words.
Many poets, including well published ones, tend to write rhyming poetry, other well published poets may never write rhyming poetry. So, as a new poet, which way should you go? The question can tie your head up in knots, so you never get any poetic words on the page at all.
The answer though is simple. Write the words down first, play with them until they shimmer and shine and can bring to the mind of the reader of your poem what you want to show them. This can be an image that struck you, a person you know, an experience you wish to share and a million other things. Then give your words to the world and let others tell you whether they can see what you wanted to show them.
You can do this in a strict poetic form, such as a sonnet or villanelle, or you can do it with the free-est free verse ever. The important thing is to get the words down and polish them until they do their work.
If you end up writing free verse, be prepared to listen to the doubters, who will never agree to free verse being poetry, rather than cut short prose. These people are wrong. That's all there is to it, they are wrong. Poetry is not prose. In prose, the words are put down on the page, one after another until you run out of room for that line and start the next. With poetry, you carefully consider where the line best ends, which word goes best with which other word, and how the whole thing looks, and feels on the page.
There have been many fine writers who have written further on this subject. I'm not going to write much more, except to say this - for me, the poem tells me whether it will be a rhyming poem, or free verse. The poem knows.