visualforce:--
<apex:page controller="importDataFromCSVController">
    <apex:form >
        <apex:pagemessages />
        <apex:pageBlock >
            <apex:pageBlockSection columns="4">
                  <apex:inputFile value="{!csvFileBody}"  filename="{!csvAsString}"/>
                  <apex:commandButton value="Import Lead" action="{!importCSVFile}"/>
               
                  <apex:selectList label="Select User:"  value="{!selecteduserId}" size="1">
                  <apex:selectOptions value="{!UsersList}">
                  </apex:selectOptions>
                  </apex:selectList>
               <!------
                  <apex:selectList value="{!selecteduserId}" size="1" multiselect="false"  >
                                          <apex:selectOptions value="{!ListOfUser}" />
                                 </apex:selectList>
                  ----->
            </apex:pageBlockSection>
        </apex:pageBlock>
        <apex:pageBlock >
           <apex:pageblocktable value="{!lList}" var="l">
              <apex:column value="{!l.Lastname}" />
              <apex:column value="{!l.Phone}" />
              <apex:column value="{!l.Company}" />
              <apex:column value="{!l.Email}" />
              
        </apex:pageblocktable>
     </apex:pageBlock>
   </apex:form>
</apex:page>



Apex:---

public with sharing class importDataFromCSVController {

    public String selecteduserId { get; set; }

 


    public List<User> UserTemp = new List<User>();
    
    
    
    public List<SelectOption> UsersList
    {
        get
        {
            UserTemp = [Select u.LastName, u.Id, u.FirstName, u.Email From User u];
           
           
            
            UsersList= new List<SelectOption>();
            
            for(User temp : UserTemp)
            {
                UsersList.add(new SelectOption(temp.Id, temp.LastName));
            }
            return UsersList;
        }
        set;
    }



    public String getUsersList() {
        return null;
    }

public Blob csvFileBody{get;set;}
public string csvAsString{get;set;}
public String[] csvFileLines{get;set;}
public List<Lead> llist{get;set;}
  public importDataFromCSVController(){
    csvFileLines = new String[]{};
    llist = New List<Lead>();
  }
 
  public void importCSVFile(){
       try{
           csvAsString = csvFileBody.toString();
           csvFileLines = csvAsString.split('\n');
            
           for(Integer i=1;i<csvFileLines.size();i++){
               Lead lObj = new Lead() ;
               string[] csvRecordData = csvFileLines[i].split(',');
               lObj.Lastname = csvRecordData[0] ;             
               lObj.Phone = csvRecordData[1];
               lObj.Company= csvRecordData[2];
               lObj.Email= csvRecordData[3];   
               //accObj.Industry = csvRecordData[4];    
               lObj.OwnerId = selecteduserId;
                                                                                    
               llist.add(lObj);   
           }
        insert llist;
        }
        catch (Exception e)
        {
            ApexPages.Message errorMessage = new ApexPages.Message(ApexPages.severity.ERROR,'An error has occured while importin data Please make sure input csv file is correct');
            ApexPages.addMessage(errorMessage);
        }  
  }
}