Because a project can represent a multitude of ideas, there are different types to suit different goals:
A sequential project is one whose actions must be performed in a certain order. The bake a cake project is a sequential project; you can't bake the cake before you buy the ingredients and you can't buy the ingredients before you find a recipe.
A parallel project is a project whose actions can be completed in any order. For example, a pay bills project whose actions are pay rent, pay cell phone bill, pay water bill, etc. This project would be considered parallel because it doesn't matter what order you pay your bills in; it just matters that they all are completed.
A single action list is a special kind of project that usually consists of projects with only one step to complete or an assortment of related actions (like, buy groceries). Often times, it is helpful to create a miscellaneous project to keep things organized.
Projects are parallel by default; if you're syncing with OmniFocus for Mac and have specified otherwise, OmniFocus for iPad will honor your preference. To specify a project type, tap a project (or create a new project) to show the editor. Then, tap the info tab, followed by the type field. Finally, choose a type from the popover.
Projects also have different statuses to reflect differing levels of completion and activity.
An active project is a project that you intend to work on. You plan on completing its actions and you have a pretty good picture about when you're going to have them done.
An on hold project is a project that you want to complete, but you're not really sure when you'll have time for it.
A completed project is a project that you've finished. Congratulations!
A dropped project is one that you haven't completed, but you don't want to move forward with it; it's abandoned. Being realistic about what you do and do not want to complete is an excellent way to find yourself spending your time wisely!
To specify a project's status, tap the project (or create a new project) to show the editor. Then, tap the info tab, followed by the status field. Finally, choose a status from the popover.
It's handy to review your projects often (about once a week) to make sure that their statuses are still accurate.