Most of android devices support now days USB OTG (On the go) cable. Using OTG cable we can connect any type of USB cable. It will allow you to connect Keyboard, Mouse, Data Card, flash drives, digital cameras etc.
Just insert OTG cable on small part on your charging socket and another part will be female socket where you can connect your external devices.
Issue during HDD Connectivity
1. May be your hard disk required more power to connect with mobile device. So logic is that your phone should be capable to handle power requirement of the device.
2. File formats on Hard disk generally now days we are keeping on your pen drive or Hard disk NTFS file system. But android support easy to go FAT32 or EX Fat.
Solutions for above issues are as follows:
Install ES File Explorer which can be easily download using Google play Store this will help you to view NTFS file format files also.
In the market 2 type of OTG Cables available. One comes with 2 port Mobile charger end and USB compatible end. But another one comes with additional Mobile Charger end that can be use to take external power.
Go to the Google Play Store download apps Paragon exFAT/NTFS USB Android open this apps and give permission to open files
Once you connect your external Hard disk on your mobile, Paragon exFAT/NTFS USB Android application will be appear mount button, just tab on that HDD will get accessible. So you can access now all your file contents using File explorer.