Ghost allows you to create custom embeddable signup forms for membership, which can be embedded within posts and pages on your site, or embedded anywhere on the web to help you grow your audience.
To create a form, go to the Settings → Membership area in Ghost Admin. From there, click Embed next to the Embeddable signup form option:
You can choose to create a branded form that includes your logo, as well as custom colors, or you can use a minimal layout if you prefer–each layout includes configurable options to make it your own.
When you've finished customizing your signup form, you can copy the embed code for use anywhere on the web.