[SalesForce] How to pass @httppost parameters in apex integration

I’m trying to integrate two salesforce orgs. How to pass httppost parameters of method from other salesforce org in apex code please find the below codes it tried but I am getting status 400 badrequest. GET method is working fine, How to pass name parameter from other org?

Mapped class of source org:

 // The @RestResource annotation is used at the class level and enables you to expose an Apex class as a REST resource.
    // more details -> https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_classes_annotation_rest_resource.htm
    @RestResource(urlMapping='/v1/getContact/*')
    global with sharing class getContact 
    {
        @Httpget
        global static list<contact> fetchContact()
        {
            RestRequest req = RestContext.request;
            RestResponse res = Restcontext.response;
            //Get input conId from the request string.
            Id conId = req.requestURI.substring(req.requestURI.lastIndexOf('/')+1);
            // Get the list of contacts by passing input conId. In this case, it will return only 1 record.
            list<contact> lstcontact =[Select id,Name,Email,MobilePhone from contact where id=:conId ];
            // return back the contact list to calling system.
            return lstcontact ;
        }
        @HttpPost
        global static string createNewContact(String name)
        {
            Contact c=new Contact();
            c.LastName=name;
            insert c;
            return 'contact sucessfully created';
        }

        @HttpDelete
        global static string deleteContact()
        {
            RestRequest req=RestContext.request;
            String ids=req.params.get('Id');
            List<Contact> c=[select id from contact where id=:ids];
            delete c;
            return 'contact deleted successfully';
        }

        @Httpput
        global static string putContact(String ids,String Name)
        {
            Contact c=[select id from contact where id=:ids];
            c.LastName=Name;
            update c;
            return 'contact updated successfully';
        }
    }

Controller class of destination org:

    public class apexintegration {

public string getContactid {get;set;}

public List<contact> outputlst {get;set;}

public List<Contact> contact {get; set;}

public string JSONResponse {get;set;}

private final string clientid='xxxxxxxxxxxxxxxxxxxxxxxxxxxxx';
private final string clientsecret='xxxxxxxxxxxxxxxxxxxxxxxxxxxx';
private final string username='xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx';
private final string password='xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx';

public class deserializeResponse
{
    public string id;
    public string access_token;
}

public string returnAccesstoken(apexintegration a)
{
    String reqBody='grant_type=password&client_id='+clientid+'&client_secret='+clientsecret+'&username='+username+'&password='+password;
    Http h=new http();
    HttpRequest req=new HttpRequest();
    req.setBody(reqBody);
    req.setMethod('POST');
    req.setEndpoint('https://login.salesforce.com/services/oauth2/token');
    HttpResponse res=h.send(req);
    deserializeResponse resp1=(deserializeResponse)JSON.deserialize(res.getBody(), deserializeResponse.class);
    return resp1.access_token;
}

public void getContact()
{
    apexintegration a=new apexintegration();

    String accesstoken;
    accesstoken=a.returnAccesstoken(a);
    if(accesstoken!=null)
    {
        String endPoint='https://curious-wolf-71m22l-dev-ed.my.salesforce.com/services/apexrest/v1/getContact/';
        Http h2 = new Http();
        HttpRequest req1 = new HttpRequest();
        req1.setHeader('Authorization','Bearer ' + accessToken);
        req1.setHeader('Content-Type','application/json');
        req1.setHeader('accept','application/json');
        req1.setMethod('GET');
        req1.setEndpoint(endPoint);
        HttpResponse res1 = h2.send(req1);
        // store raw JSON response
        JSONResponse = res1.getBody().unescapeCsv().remove('\\');
        contact = (List<Contact>) JSON.deserialize(JSONResponse, List<Contact>.class);

    }
    outputlst= contact;
}

public void createContact()
{
    apexintegration a=new apexintegration();

    String accesstoken;
    accesstoken=a.returnAccesstoken(a);
    if(accesstoken!=null)
    {
        String endPoint='https://curious-wolf-71m22l-dev-ed.my.salesforce.com/services/apexrest/v1/getContact/';
        String body= 'name=saivinaymnprm';
        Http h2 = new Http();
        HttpRequest req1 = new HttpRequest();
        req1.setHeader('Authorization','Bearer ' + accessToken);
        req1.setHeader('Content-Type','application/json');
        req1.setHeader('accept','application/json');
        req1.setMethod('POST');
        req1.setBody(body);
        req1.setEndpoint(endPoint);
        HttpResponse res1 = h2.send(req1);
        JSONResponse = res1.getBody().unescapeCsv().remove('\\');
        String s=(String)JSON.deserialize(JSONResponse, String.class);
        System.debug(s);
}

}