FYI, IP address which is unchanged for months or years at a time is called a static IP address.
An IP which is only good for a limited time, and which is changed according to the policy set by your ISP's DHCP server, is a dynamic IP address.
A static IP can be relied on for an indefinite period, some networking software requires a static IP. ISPs usually charge extra for static IPs. Your ISP (Internet Service Provider) may not be willing to give their customers static IP addresses at all.
Dynamic IP is used in large networks where computers are frequently reconfigured, or where a limited number of IP address are available to share between many computers.
So, if you are asking "How to get dynamic IP for your internet connection” then, that’s done automatically unless you have asked your internet service provider to assign a static IP address to your account. If that’s the case, just call your internet provider and ask them to remove that static IP address from your account.
I home this helps :)