How do you create a lag report from the date and time a record was created and information in a form?

If you have some date field you want to compare it to you can use the date created compared to the [Date Field].

Keep in mind that [Date Created] is a date/time field, so you will need to convert it to date only before your do the arithmetic to find duration.

[Key Date Field] - ToDate([Date Created]) = Duration

If you want to go from date created to today:

Today()-ToDate([Date Created])

From this moment:

Now()-[Date Created]

Hope this helps point you in the right direction.