I have been searching for quite awhile and have not found the answer yet.
How can I get subscribe link to my subscribe newsletter button?
I have created smart list containing those who will be joining the list
I saw some suggestion to use coding and Flow -> add to smart list, but I wonder if I can do simple link?
This time around we will not do form.
Where are you trying to place this link?
If it is a button in an email I would use the button ID. Do a smart list and do clicked on email with a constrain for email ID once you had specified that ID.
If its on a landing page you can do clicked a link on a webpage as one of the options.
You can also do a form with no fields are simply a trigger off of the form submit.
We need to understand how you want to use this link to better guide you but the above are all options.
Never trigger on Clicked Email. Mail scanners will click your links and opt people in without their consent. Always require manual interaction.