OSAP stands for Objective-to-strategy-to-action plan. It is one of the most recommended tools for structured task planning & execution.
OSAP is part of a practical planning process called VMOSA – Vision, Mission, Objectives, Strategies and Action Plan. VMOSA enables you to work your way from the vision and all the way down to the action plan. In essence, this tool helps a company create a blueprint through defining and aligning practical approaches for achieving a vision.

The company vision and mission are most likely defined before you join. Your contribution comes in planning and executing tasks or solutions, so OSAP is the tool that you will employ for tasks of medium to high complexity.
In a practical manner, the tasks given by your manager will be your objectives. In order to meet the objectives, you will need to define the broad approaches – these being your strategies. However, strategies are oftentimes phrased vaguely. In order to make your strategy more specific for you and others to execute, an action plan must be created to specify the steps required.
Start structuring your solutions and suggestions using OSAP / Objective – Strategies – Action Plan.