Using Google Sync to Transfer Contacts:

You can sync the contacts stored on the HTC One S with a Google account, making it very easy to transfer the contacts over to the HTC One E8. Once the contacts are synced, all you need to do is to re-sync them with the One E8, as explained below

1. On the HTC One S, register your Google account
2. Go to the phone's "Settings" menu
3. Tap "Accounts & sync" > "Google"
4. Select the desired account
5. Clear and then mark the "Contacts" check box. Alternatively, tap "Menu" > "Sync all"
6. On the HTC One E8, register the same Google account as the one used on the One S
7. Tap "Apps" on the E8's home screen and then go to "Settings"
8. Tap "Accounts & sync" and select a Google account
9. Set the account so that it can sync contacts with your One E8

Using the "Import / Export" Option in the "People" App:

Using the "People" application, you can export the contacts stored on the One S and share them via email or using a computer. Using the same app, the exported contacts can be imported on the HTC One E8 with ease, as explained below:

1. Open the "People" app on the HTC One S
2. From the "People" tab, tap "Menu"
3. Tap "Manage contacts" > "import / Export contacts"
4. Tap "Export to phone storage"
5. Choose an account and write down the export file's name before pressing "OK"
6. Launch the email client and then compose a new email
7. Attach the vCard file to the email and send it to your Gmail address
8. On the HTC One E8, open the email and download the attached file
9. Once the file is downloaded, launch the "People" app
10. Go to the "People" tab and then tap "Menu" > "Import / Export contacts"
11. Tap "Import from storage" and browse for the downloaded vCard file to import on the E8's phonebook

NOTE: Once you have created the VCF file on the HTC One S, you can transfer it to the HTC One E8 by connecting both smartphones to your computer via USB, and copying > pasting the file to the E8's "sdcard" directory. Once that's done, open the "People" app and import the file's contents to the phonebook

Transferring Contacts via "Send Anywhere":

Last but not least, "Send Anywhere" is a third party app that can be used to transfer various types of files, including contacts via a P2P connection. For this method of transfer you do not require access to a computer

1. Visit the Google Play Store and install "Send Anywhere" on both Android smartphone
2. After the app has been installed, launch it on both smartphones
3. On the HTC One S, tap "Send"
4. Tap "Contacts" and mark the contacts that you wish to share
5. Tap "Send" and then select a method of transfer. By tapping "Generate QR Code" on the HTC One S, you can create a QR code which can be scanned with the One E8's camera to start the transfer. Tapping "Receive" on the E8 will allow you to enter the randomly generated transfer code from the HTC One S