Forming an LLC is easy and can be done online at the secretary of states web site.
https://sos.iowa.gov/
Use the search feature to look for existing businesses in Iowa that are similar in nature to what you are looking to do. Download 2 or 3 different articles of incorporation then take the parts you like from what you see to make your own.
Someone else mentioned an operating agreement which isn't important right away specially if you are just on your own. If you have a partnership or multiple people involved an operating agreement is important. It isn't a bad idea to have a lawyer help you with this part.
As to the person wondering if it is sketchy to start in business without the legal paperwork, no there is no need to file paperwork before you get started unless of course you are in a trade that requires licensing. There is also sales tax collection which requires a separate state account.
I would be VERY careful with this aspect.
The legal paperwork serves two purposes: to make your business official in the eyes of the government (hence legal and taxable) and to create a "guideline" in case the company goes under or a founder/key figure leaves.
Be VERY VERY careful who you pick as a cofounder. I have witnessed hundreds to thousands of businesses being started; the founders that chose a random cofounder to fill a need fell apart almost every time. I would recommend you find someone you have worked well with in the past or a friend that will enjoy working with you. I would also recommend that you pick someone who has a passion for it and would do the project anyway if you weren't there. Ask them, if I died in a week, would you continue to work on this? If the answer isn't "absolutely", they may not be in it for the long hall.
The legal document does not bind you two (or more) together to fight for the common goal. It is just for court when you guys either go bankrupt or someone decides to leave. It does not assign your roles, those should be known by your relationship and discussions. If you need to utter the words "We have an agreement that...", you clearly didn't come to an agreement.
I strongly suggest finding a cofounder, but don't bring one on if you don't have a prior history of working together. Also, I have seen husband and wife teams work; however, I would NEVER start a business with my wife. We are both DOMINANT personalities and we would clash non-stop. Great marriage, but terrible business partners.