What is the difference between different OPORD formats?

There is a NATO standard OPORD format that you'll see in 6-0. But local S3 operations will almost always have their own specific versions

Refer to FM 6-0 for specific guidance

FM6-0 is the standard unless local SOP has superseded it. There were some variations based on mission type, like the patrol order format used in the Ranger Handbook, or some SOP adjusted orders for route reconnaissance. They would vary by the unit executing it and the key elements of the operation. In a Sustainment unit, Paragraph 3 is focused on concept of support because that is the operation they perform, and security/protection tasks are an add on.

What other order formats are you talking about in your comment? Sources? It may help us help you answer this question.

In general terms, the order format with all annexes are something a staff at the BN and above would prepare and issue. Certainly not the level and scope of what a Squad,Platoon, or Company would produce to issue to their subordinate units/soldiers.

The Unit's Mission (two Command levels up/one level down) and the Commander's Intent determine what components are present within the OPORD. Annexes extend the OPORD structure for those areas the are needed to conduct the mission.
FM 6-0 provides the tactics and procedures associated with mission command but not all.
Why include all the Annexes A through Z, there is no need? Example: Sample Annex N (Space Operations).
Commanders determine at what level the various components are disseminated and what his reporting procedures they want their staffs to monitor.
All of the above is known as the Military Decision-Making Process (MDMP).
Troop leading procedures (TLP) extend the MDMP to the small-unit level below the Commander level.

The format in FM 6-0 is provided to ensure that all factors which may impact the mission are considered. Paragraphs which are irrelevant may be omitted.

Lots of great responses here. 1LT Ting-Yu C., if you are building a training scenario go with FM 6-0, my rule of thumb has always been to reset to doctrine whenever possible. Soldiers need to know the doctrine format, then you can teach how the local SOP differs and why. There is usually a pretty good reason.

The biggest different in formats is how in depth you want to go and where you are putting info that could go in different places. For example, since you are aviation you coul have a task to aviation units in para 3. Even this version is at least 9 years old as para 4 is called sustainment and para 5 is command and control.

For Army operations I advise using FM 6-0. A doctrinal foundation provides a common operating picture to ensure Soldiers understand the format and contents in a simple fashion.