Please follow the procedure below:
Step-1: Search on google by typing (developer google youtube subscriber button).
Step-2: Click on the Google showed link which is the title(Configure a button|youtube button| Google developers).
Step-3: Fill up your channel name either id then fill up the next following options those are located under configure a button.
Step-4: Copy the HTML code which is located under the preview tab.
Note: save the code & refresh your blog either website to see your own subscriber button.
Content writer: Sheikh Md S Hoque