Beginning in v2.44, Memberium provides an out-of-the-box integration with Ninja Forms, which enables you to use the familiar and easy to use shortcode system. You may be familiar with this feature as “Autofill”.
While more expensive, we recommend using Gravity Forms instead. The licensing is less arbitrary and the product and add-on ecosystem are far more mature and robust than Ninja Forms.You can get Gravity Forms here
You can download Ninja Forms from this link or simply go to Plugins > Add New > Search for Ninja Forms > Install > Activate.
Creating Your First Ninja Form
Once you have activated Ninja Forms, you can access it on your WP menu.
Ninja Forms enables you to easily build forms for your website. To create your first Ninja Form, click on “Ninja Forms” > Dashboard > Add New
You can then choose what kind of form you would like to create.
Setting Up AutoFill
To specify a field on your form for autofill, click on the gear icon on the right side of the field.
Go to the “Advanced” drop down in your form’s field and enter the memb_contact shortcode.
Click on “Done” and Publish.
Other References
Choosing a WordPress form plugin: Gravity Forms, Ninja Forms, or Formidable Pro?