The "Subscribe now" button is dynamic; what a reader sees in an email or on a web post depends on their personal subscription status.
For subscribers of free publications
Subscribers who receive an email or are signed into their Substack account and view your web post will see a "Subscribed" button with a checkmark confirming that they're already subscribed to your Substack publication.
Tip: If you have Pledges enabled on your publication, subscribers will see a "Pledge your support" button.
For free subscribers of paid publications
Free subscribers who receive an email or are signed into their Substack account and view your web post will see an "Upgrade to paid" button.
Note: If you have payments enabled on your publication, paying subscribers will see a "Subscribed" button with a checkmark.
For general readers
If a reader comes across your web post and isn't subscribed to your Substack or signed into their Substack account, they'll see the Subscribe button with an empty email field.