RE: Personalized page content
Hi Marco,
As first paragraph of documentation introduced: sometimes we may embed a landing page into marketing email, when recipient opened the page, it will display content that's personalized for known contacts.
Below is my sample:
1. Create a marketing form, set prefilling feature to both form level(In Summary tab) and field level(In form design tool).
2. Create a new "Personalized page" record, add a field of Contact entity as whitelisted field for personalized content.
Then paste automatically generated code to marketing page.

3. Create a marketing email and add landing page with script.

4. After recipient opened the link, we can get the whitelisted field value from embedded script then design personalized content.

my code:
window.msdyncrm_personalizedpage = {
id: "2ba18988-abc4-ea11-a812-000d3ab64f2b",
endpoint: "https://c976ae42b0574b03b8e738e902ade391.svc.dynamics.com",
success: function (data) {
var firstname = data.Data["firstname"];
alert("Hi, " firstname);
},
error: function () { }
};
(Here is another sample from the previous thread: https://community.dynamics.com/365/marketing/f/dynamics-365-for-marketing-forum/373750/microsoft-ignite-marketing-demo)
Obviously, we can also embed the script into subscription center page for personalization.
Regards,
Clofly