Where to find it
Your handle is under your channel name. A full youtube.com/channel/... link works too.
One thing to check
Only Public and Unlisted uploads can be reached. A Private video is locked to everyone except you.
What subscribers do for you
A stranger who lands on your channel checks the subscriber number before almost anything else. Worth knowing: getting into the YouTube Partner Program also needs real watch hours, so subscribers alone won't unlock monetisation.