With Karmasoft you can add buy now links to your website or emails.
From the dashboard, click [Assets] and [Products].
From the product screen, click on the product you'd like to sell online. *Note: make sure the sell online box is checked on this product. If it's not, check it now. Then click save, and re-open your product screen.
Highlight and copy your shopping cart URL.
Paste the shopping cart URL within an HTML link:
<a href="YOUR SHOPPING CART URL">Buy Now</a>
For a quick tutorial see: https://www.w3schools.com/tags/att_a_href.asp