Yes, simply create the Update Query and use a reference to the form for the
values.
For example, create a form in NWind called UpdateExampleForm.
Add 2 text boxes, NewName and EmpID
Stick in 1 for Emp ID and "Jane" for New Name
Run the following to demonstrate using the form for both criteria and values
UPDATE Employees SET Employees.FirstName =
[forms]![UpdateExampleForm]![NewName]
WHERE (((Employees.EmployeeID)=[forms]![UpdateExampleForm]![EmpID]));
You should see Nancy Davolio change to Jane Davolio