Do members have to have a Shopify Account?
If you want your customers to be able to manage their memberships themselves (ex: upgrade or cancel their membership, modify their credit card information, etc), you will need to enable customer accounts within Shopify. To do that, go to your Settings > Checkout section and make sure that customer accounts are required:
You may also want to encourage your customers to sign up for an account in your membership welcome email so that they can manage their membership themselves. To edit that email, simply head to the Email Settings tab of your membership details page within Conjured Memberships.