The LLC is created to protect your personal assets and to separate your personal business from your investment business. There are many reasons why it's a good idea to create an LLC and quit claiming your business property to the LLC. Insurance is great and absolutely required but it may not be sufficient if a renter or tenant comes after you.
I have always suggested that investors go in highly leveraged. While this is still a good strategy if you can afford it, the next best thing it does is to keep the wolves away. Judgments against an LLC with the property that is secured by a mortgage of 80% or more are not likely to attract ambulance chasers.
Even if you pay cash for the property, create a mortgage for the property through a trust you set up so that the property has sufficient liens to keep the bad guys from your business.
You can set up an LLC by going to the Secretary of State's website in the state where the property is located. Create the LLC by paying with a credit card. If you do not live in that state, you will need the services of a registered agent, easy to find online.
The reason for creating the LLC in the state where the property is located is that you will be permitted to use the courts in that state if you need to initiate litigation. A foreign company can not use state courts unless you create the business in the state or register as a foreign company.
You will need to create an operating agreement. You can find samples online. This is your document. Most if not all states do not have a mandatory template. There are some important items to be included but you simply say what you want about who owns want etc.
Apply for a federal tax ID number online at the IRS site. Do not be fooled by the fake sites that charge you. The IRS has no fees.
You are now prepared to open a bank account.
Next, create a quit claim deed to transfer your property to the LLC. You can usually get samples of the format from the County Recorder or Court employee who accepts deeds for recording. Get the document notarized and file it.
Regarding the due-on-sale clause. Most finance companies do not recognize the transfer as a sale. The due on-sale clause requires a sale. While technically it is a sale, there is a connection to the mortgagor. I am not offering advice here, check with your mortgage holder to be sure.
You may or may not want to see an attorney about the above. If you decide to, contact one in the area where the property is located and one that is a "business" attorney. The action of creating the LLC with the state is simple and you should be able to do that without an attorney. Use the attorney to create the agreement and possibly handle the quit claim deed.