How to make key and value (username and password) dynamic in API connect

{
"loginTokens": [
    {
        "key": "com.abc.security.provider.login.email",
        "value": "abc.xyz@xyz.com"
    },
    {
        "key": "com.abc.security.provider.login.password",
        "value": "abc@123"
    }
],
" apiVersion": "{\"major\": \"1\",\"minor\": \"0\",\"patch\": \"0\",\"build\": \"0\"}",
    "purpose": "dpay-auth",
"tokenLocation": "HEADER"}

In above json i need to give value(email) and value(pwsd) through user.