Even if you are not required by your state to have an Operating Agreement, it is a good idea to have both an Operating Agreement and a Business Plan. While most businesses start with an idea, an idea cannot run your business. A well-thought-out Operating Agreement can help you prepare for difficult situations, and a solid Business Plan can help you outline the strategic vision for your company's growth and success.

And a good Business Plan generally includes:
-A clear description of your product or service
-Who the stakeholders are and their roles
-A researched marketing plan
-A financial plan
While in some cases a handshake agreement may be proven valid if it needs to be enforced, it is better to have a written agreement. Some laws require written contracts, such as certain real estate transactions. Additionally, there are laws that require contracts for agreements that may last longer than one year.
A sample list of business agreements you should get in writing:
-Any real estate sales contract
-Commercial and residential lease agreements
-Sales agreements for large purchases
-Service agreements for costly jobs
-Partnerships or joint venture agreements
-Loan and investment contracts
-Agreements that last longer than a year
-Agreements that last past the death of one of parties

Business and contracts
Non-Disclosure Agreement
LLC Operating Agreement
Independent Contractor Agreement
Business Contract
Real estate
Lease Agreement
Eviction Notice
Intent to Purchase Real Estate
Quitclaim Deed
Family and personal
Last Will and Testament
Living Will
Divorce Settlement Agreement
Child Care Authorization
Personal

Health and Medical
Divorce and Legal Separation
Children
Driving and Automotive
Business

Incorporation
LLC
Running a Business / Compliance
Intellectual Property and Licensing
Labor and Employment
Property & Finance