Did you go to a new record first?

Here's my setup :

Here's the Code I'm using:

Private Sub BtnSaveInventoryLevel_Click()

    If IsNull(TransactionQty) Then
        DoCmd.GoToControl "TransactionQty"
        Exit Sub
    End If
            
    DoCmd.GoToRecord , , acNewRec
    Forms!TrackedInventoryInformationF!TrackedInventoryUsageSubF.Form!TransactionDate = TransactionDate
    Forms!TrackedInventoryInformationF!TrackedInventoryUsageSubF.Form!UsageAmount = TransactionQty
    Forms!TrackedInventoryInformationF!TrackedInventoryUsageSubF.Form!TransactionType = TransactionType
    
    DoCmd.Close acForm, Me.Name, acSaveYes
  
End Sub

You need to set the focus to your Subform object before going to a new record.

TrackedInventoryUsageSubF.SetFocus
DoCmd.GoToRecord , , acNewRec

Make sure Allow Additions is set to Yes.
If you need Allow Addition to be No then turn them on before the code, then turn them on again after.

Forms!TrackedInventoryInformationF!TrackedInventoryUsageSubF.Form.AllowAdditions = True
'
'
'
Forms!TrackedInventoryInformationF!TrackedInventoryUsageSubF.Form.AllowAdditions = False

Hey, the Data on the Single Form that I am trying to Add to Continuous Form will not input into the Continuous Subform on the Main Single Form. I can not get the Form the Add New Records into the Continuous Form. It just changes the Data in the Table, not Add the new Record to the Table.

"Add Additions" is set to Yes
"Data Entry" is set to No

On all Forms

I may have to Insert the Data from the Single Form, that's not bound to nothing, into the Table instead of the Continuous Subform.

Hey guys, how can fix problem of, the Data on the "Add, Subtract, or Reset Inventory Level" Single Forms that I am using to Add the Data to "Usage Continuous Subform". The Form will not input into the "Usage Continuous Subform" on the Main "Track Inventory" Single Form. I can not get the Form the Add New Records into the Continuous Form. When transfering the the "Usage Continuous Subform", it just changes the Data in the Table and not "Add the new Record" to the Table or Continuous Form'

James
You may want to go watch the Invoicing videos. (or re-watch if you already have)
Especially the extended cut.

Why? If you think about it, receiving inventory is pretty much just the reverse of what you are doing in adding an item to an order. For an order you are taking items out of stock.  
The same concept could be used to bring in inventory - Add items to your stock level.

Other videos that may be of help:
Inventory
Manage Rental Inventory

Hey, Scott, I have watched the Tech Help Videos several times to double check to see if I was missing something. I have the same setup in my "Invoice, Estimate, Contract, and Purchase Order Detail Subforms" with using the Combo Box and a Button to Insert the Data into the Continuous Form. I haven't get it to work with an Standalone Single Form to Insert into the Continuous Subform.

I also tried what Kevin was saying:

TrackedInventoryUsageSubF.SetFocus
DoCmd.GoToRecord , , acNewRec

Make sure Allow Additions is set to Yes.
If you need Allow Addition to be No then turn them on before the code, then turn them on again after.

Forms!TrackedInventoryInformationF!TrackedInventoryUsageSubF.Form.AllowAdditions = True
'
'
'
Forms!TrackedInventoryInformationF!TrackedInventoryUsageSubF.Form.AllowAdditions = False

Have you tried using an INSERT INTO statement? Then Requery the Subform.

James -
Keep in mind that a form is just a way of interacting with the fields and data in a table (generally).
Rather that trying to put something into a form, you are entering or modifying data into a field. Then, if your other form is open in the background, your events just tell Access, "Hey I made a change. Go out and get the new information and load it into that other form."

I know it isn't exactly what you are trying to do here but go watch the Event Enrollment videos.  In it Richard shows how when a payment is made the totals are updated in the subform of the EventF and also in the EventListF.  The Lego pieces may look different but the concept is the same.  It is just how you put the pieces together.

Scott and Kevin, y'all guys are awesome... I was thinking about it and wrong. Tieing the Single Form the table and Requerying the Surform, gets exactly I was looking for to do. Thank again for your time and help.