Sorry, I should have expressed myself correctly. Unfortunately, I can't put any pictures online. 

For example, I would like that when we activate the button at the allergens "Field: x_studio_ei Model: product.template, Type: boolean, Widget On/Off (boolean_toggle), Context: {}" it appears on the product detail page in the shop.

I would also like this information "Field: x_studio_product_feature_4, Model: product.template, Type: char, Context: {}" to also be displayed on the product detail page in the shop.

You need to modify the XML view for the product template. First, activate developer mode.
Locate the Product Template View: Navigate to Settings > Technical > User Interface > Views and search for the view named "product.template.form" or a similar name related to the product form you are trying to modify. Then edit the XML view and add your custom field to the desired location within the XML.
You should place the tag field tag with name="x_studio_ei" in your desired location.