Found this instruction at simply-access.com.
Answer
The problem with both forms and reports is that if you add fields to your table, these are not then automatically added to the query that underlies the form or report - you have to do this manually.
You may not even realise your form or report is based on a query and, to confuse you even more, the query does not exist in the Query Object section of the database. What happens is that if you follow the Wizard to build a form or report based on more than one table, Microsoft Access automatically builds a query to base the form or report on and then stores this query with the form.
To manually add a field to this query:
Open the form or report in Design view;
Open the properties to the form or report by right clicking in the grey square on the upper left-hand side of the form or the report (where the two rulers meet), then selecting 'properties' from the drop down list.
With the properties window open, click on the 'Data' tab then, next to 'Record Source', click on the '...' button. This will open the query the form or report is based on.
Add the new fields by double clicking on them.
Close and save the query.
Your fields should now be in your field list.
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