Use of Mini Program Request Header

We generally use request headers when encapsulating network modules and request data. Different request headers are used according to different data.
Generally we use

 header: { 'Content-Type': 'application/x-www-form-urlencoded' }

When the data is json, pass the data

 header:{'content-type':'application/json;charset=utf-8'}

If there is anything wrong, please give me some advice.