public void APICALL()
   {

     HttpRequest req = new HttpRequest();
     String endPointURL = 'https://abcwerr.ffff.com/v2/ttttt';
    String userName = 'BlahBlah';
    String password = 'BlahBlah';
   Blob headerValue = Blob.valueOf(userName + ':' + password);
    String authorizationHeader = 'Basic' +
    EncodingUtil.base64Encode(headerValue);
     req.setEndpoint(endPointURL);
    req.setHeader('Content-Type', 'multipart/form-data');
    req.setHeader('Authorization',authorizationHeader);
    req.setMethod('POST');
    string bdy = 'merchant_url='+ AppForm.Business_Website__c;

    req.setbody(EncodingUtil.base64Encode(bdy));
    Http http = new Http();

    HTTPResponse res = http.send(req);
    this.SpiderResponse = res.getBody();
   }

Blob headerValue = Blob.valueOf(username + ':' + password);
String authorizationHeader = 'Basic ' + EncodingUtil.base64Encode(headerValue);
r.setHeader('Authorization', authorizationHeader);