I have replicated your problem with this solution, It is not tested but I believe it will point you to a good direction.
To save within your app, you might do this
Layout file 
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.inducesmile.emailapplication.MainActivity">
<EditText
   android:id="@+id/nameRegistration"
   android:layout_width="match_parent"
   android:layout_height="wrap_content"
   android:hint="Enter name"
   android:layout_alignParentTop="true"
   android:layout_centerHorizontal="true"/>
<EditText
    android:id="@+id/userStreetAddressRegistration"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:hint="Enter Address"
    android:layout_below="@+id/nameRegistration"
    android:layout_marginTop="8dp"
    android:layout_centerHorizontal="true"/>
<EditText
    android:id="@+id/userCityRegistration"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:hint="Enter City"
    android:layout_below="@+id/userStreetAddressRegistration"
    android:layout_marginTop="8dp"
    android:layout_centerHorizontal="true"/>
<EditText
    android:id="@+id/userStateRegistration"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:hint="Enter State"
    android:layout_below="@+id/userCityRegistration"
    android:layout_marginTop="8dp"
    android:layout_centerHorizontal="true"/>
<EditText
    android:id="@+id/userZipRegistration"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:hint="Enter Zip Code"
    android:layout_below="@+id/userStateRegistration"
    android:layout_marginTop="8dp"
    android:layout_centerHorizontal="true"/>
<EditText
    android:id="@+id/userPhoneRegistration"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:hint="Enter Phone Number"
    android:layout_below="@+id/userZipRegistration"
    android:layout_marginTop="8dp"
    android:layout_centerHorizontal="true"/>
<EditText
    android:id="@+id/userEmailRegistration"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:hint="Enter Email"
    android:layout_below="@+id/userPhoneRegistration"
    android:layout_marginTop="8dp"
    android:layout_centerHorizontal="true"/>
<EditText
    android:id="@+id/userDOB"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:hint="Enter DOB"
    android:layout_below="@+id/userEmailRegistration"
    android:layout_marginTop="8dp"
    android:layout_centerHorizontal="true"/>
<Button
    android:id="@+id/submit_button"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Submit"
    android:padding="20dp"
    android:layout_marginTop="16dp"
    android:layout_below="@+id/userDOB"
    android:layout_centerHorizontal="true"/>
</RelativeLayout>
Activity Page
import android.content.Context;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import java.util.HashSet;
import java.util.Set;
public class MainActivity extends AppCompatActivity {
private EditText userName;
private EditText userStreetAddress;
private EditText userCity;
private EditText userState;
private EditText userZip;
private EditText userPhone;
private EditText userEmail;
private EditText userDOB;
private SharedPreferences prefs;
private boolean hasDataBeenSaved;
private Set<String> set;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    prefs=this.getSharedPreferences("settings", Context.MODE_PRIVATE);
    set = prefs.getStringSet("Personal Information", null);
    if(set.size() > 0){
        hasDataBeenSaved = true;
    }
    if(hasDataBeenSaved){
        // display the store personal information
    }
    userName = (EditText)findViewById(R.id.nameRegistration);
    userStreetAddress = (EditText)findViewById(R.id.userStreetAddressRegistration);
    userCity = (EditText)findViewById(R.id.userCityRegistration);
    userState = (EditText)findViewById(R.id.userStateRegistration);
    userZip = (EditText)findViewById(R.id.userZipRegistration);
    userPhone = (EditText)findViewById(R.id.userPhoneRegistration);
    userEmail = (EditText)findViewById(R.id.userEmailRegistration);
    userDOB = (EditText)findViewById(R.id.userDOB);
    Button submitButton = (Button)findViewById(R.id.submit_button);
    submitButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if(!hasDataBeenSaved){
                // Data has not been save then save them
                String name = userName.getText().toString();
                String address = userStreetAddress.getText().toString();
                String city = userCity.getText().toString();
                String state = userState.getText().toString();
                String zip = userZip.getText().toString();
                String phone = userPhone.getText().toString();
                String email = userEmail.getText().toString();
                String dob = userDOB.getText().toString();
                if(!isEmpty(name) || !isEmpty(address) || !isEmpty(city) || !isEmpty(state) || !isEmpty(zip) || !isEmpty(phone) || !isEmpty(email) || !isEmpty(dob)){
                    Toast.makeText(MainActivity.this, "All input field must be filled", Toast.LENGTH_LONG).show();
                    return;
                }
                Set<String> set = new HashSet<String>();
                set.add(name);
                set.add(address);
                set.add(city);
                set.add(state);
                set.add(zip);
                set.add(phone);
                set.add(email);
                set.add(dob);
                SharedPreferences.Editor edit = prefs.edit();
                edit.putStringSet("Personal Information", set);
                edit.commit();
            }
        }
    });
}
private boolean isEmpty(String input){
    if(input.equals("")){
        return true;
    }
    return false;
}
}
For sending the information to your email, you can either use the 
- Android Intent - Intent emailIntent = new Intent(android.content.Intent.ACTION_SEND);
 
In this case, it will just launch a client email application 
- If you want to use a button click to send email with all user inputted information available, then refer to this link - Sending Email in Android using JavaMail API without using the default/built-in app