Follow the below steps for guidance –
Step 1: Go to Membership >> Plans >> Click on Menu icon >> Click on Get button and copy the code.
Step 2: Now, navigate to Online Store > Themes > Actions> Edit code(Published Theme).
Step 3: Open file “product-template.liquid” and search for keyword “cart“(button needed above or below the cart button). After that, paste the copied code above or below it.
Step 4: Click on Save.