By default, YouTube subscription is private. So, you can only see a list of your YouTube channel subscribers who have set their subscription as public.
Here is how you can see your subscribers on YouTube web version (PC):
At the top, besides "Subscribers," you can see your total subscribers count. Beside it, you can see a drop-down list in which you can see the options to sort your subscribers by their popularity or subscription time.
Click on a subscriber name, and it will take you to their channel.
Beside subscriber name, you can notice how long they are a subscriber to you, how many subscribers they have, "Subscribe" button which you can use to subscribe to their channel, and "Send message" button which you can use to send the message to them.
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How to See Your Subscribers on YouTube