To use a custom permalink or permanent link just edit your post and in right site of your Edited Post you will see like below
By default blog keep it “Automatic URL” with your current post title. But If you want to specify a custom URL, opt for the “Custom URL” option and you can enter your custom post permalink over there. It will allow you to enter alphabets, hyphens and underscores. Enclosure Links Help you make Podcasts, Mp3s and other content in your posts playable in feeds like RSS and Atom. Remember that it will ignore underscores. So you can use a combination of hyphens and alphabets to create your post permalink.
The Final Permalink will be something like below