Can I write a query that will select the last (current) record I was in on an input form. So I can then put a command button on the input form that would run a macro which uses the query for complete an action for that record only.

If you can identify the record uniquely based on values of a field then you can put the following in the search criteria of the query:

Forms![FormName]![FieldName]

Alternatively, you probably could convert whatever your macro does to code and run it from the form (using that record) directly.

I haven't explained my problem very clearly. I want to insert the name and address from the current record on a form into a Word document which contains mail merge fields. It is simple to use a query for mail merging multiple records but I have no idea how to insert a one off record. I know it has to be done from the Access end otherwise how would Word know what to merge and presumably by creating a query for it to feed off.