Based on what you provided, it is pretty simple for what you need to do and you even have a number of ways to go about doing it. You'll need something that'll let you post a body with your request. Almost any programming language can do this as well as command line tools like cURL.
One you have your tool decided, you'll need to create your JSON body and submit it to the server.
An example using cURL would be (all in one line, minus the \ at the end of the first line):
curl -v -H "Content-Type: application/json" -X POST \
-d '{"name":"your name","phonenumber":"111-111"}' http://www.abc.com/details
The above command will create a request that should look like the following:
POST /details HTTP/1.1
Host: www.abc.com
Content-Type: application/json
Content-Length: 44
{"name":"your name","phonenumber":"111-111"}