Is there a way to automatically assign initial fields to each page for each participant?

Hello Joannaw75509803,

You would need to manually add each Initial field at desired location in document and also, if you want, you can use text tags instead which you would add in document before uploading it in EchoSign and form fields would be created automatically. Below, is the documentation for same:

https://helpx.adobe.com/document-cloud/help/adding-esign-services-agreement-fields.html

Regards,

-Rijul