You can allow your customers to choose multiple answers when answering a question. For example, your customers could be allowed to choose two types of feathers on a hat.
Selecting the Checkbox input type
You can select the checkbox input type, which always allow your customers to choose multiple selections.
Activating the 'Multiple Selection' setting for Thumbnail, Dropdown or Label input types
Open your product.
Create a question by clicking on the blue + button.
Pick Thumbnail, Dropdown or Label as your input type.
Pick Image or None as your display type.
Open the properties panel of your question (located on the right side of the screen).
Add more than one answer to your question.
Under Input type, toggle on the Multiple selection setting.
NOTE
If your answers contain images, they will be displayed in the order in which they were selected.
Limiting the number of selections to a minimum and maximum
Open your product and select the question for which you want to set a maximum or minimum number of selections.
In the right side panel, next to Input type, click on the setting icon.
Set you minimum and maximum number of selections.