Signature fields in documents can be assigned one of two ways. If your document is an interactive document that has been properly set up to autofill you can assign fields automatically. This option will prompt you immediately upon opening one of these documents for the first time.
If you have already opened the document, or previously autofilled it, you can always access the autofill window across the top menu bar when within a document.
Alternatively, if the document is not set up to autofill, any field in dotloop can be assigned to a specific person. To do this, first click on the field you wish to assign. This will prompt a second menu bar to appear at the top.
In this new menu bar will be an area that will show you who the field is currently assigned to. You have the option now in this menu to assign the field to either a specific person (allowing only that person to interact with that field), a specific role (allowing anyone with that role to interact with the field), no one (which allows no one to interact with the field), or anyone (which will allow anyone with access to the document to interact with the field).