Increasing autonomy by delegating a task
Delegation can be an opportunity to increase motivation through autonomy. Here's a simple way to provide independence without losing control by doing so.
Define mission constraints
Giving more autonomy does not mean giving carte blanche. Explain the constraints you have regarding Budget and Means so that he/she can act accordingly. As part of the budget, you can allocate an envelope and let it be used freely.
You can say, "I want you to take care of[Mission name]. For that we have an envelope of[amount]. I leave you the freedom to use this amount as you wish.”
Outside the constraints, give carte blanche
Outside the constraints, he/she can achieve the objective, no matter how. Let him/her organize his/her work as he/she wishes. A report has to be made? Let him/her present as he/she wishes (Powerpoint, video, whiteboard, Prezi, ....). A customer needs to be canvassed? Let him/her choose the CRM he/she likes according to the budget.
You can say: "Now that you know the budget and the tools, you have carte blanche for[Goal]. You can use whatever means you have.”