How do I make a comments history on Microsoft access

Here is the reference for the ColumnHistory method:

Application.ColumnHistory method (Access) | Microsoft Learn

Here is a link to related question with more information about the AppendOnly property for Long Text (memo) fields:

Access Memo Field Append Only - Microsoft Comunity

I hope this helps you with your solution.

Access templates are designed as examples of how to do things in Access. Sometimes the templates use features that most developers eschew. This appears to be one such case. As Ken has said, using a memo field to store multiple comments is inefficient. Maintaining a log of comments can be done much simpler.

tblAssetcomments

AssetcommentID (PK autonumber)

AssetID (FK)

CommentDate

Comment

Then simply add a subform to your main Asset form linked on AssetID and you can add new comments and see a history of comments.

According to the documentation the first argument of the ColumnHistory method should be a table name.  Referencing the form's RecordSource property therefore, would require the RecordSource property to be a table name.  Is that the case with your form?  I don't see any cogent reason for doing this rather than using the table name as a literal string.  Substitute the table name, delimited by quotes, and set the long text (memo) field's AppendOnly property to True, and you should have no problem.

However, rather than using the long text field as a data structure, a better solution, in my opinion, would be to decompose the table so that the Comment field is in a separate related table along with a foreign key referencing the primary key of the current table, and a DateTimeStamp column. The primary key of the related table would be a composite of the foreign key and DateTimeStamp columns.  Each comment would be a separate record in that table.  For data input a subform containing only the Comment text box control, in continuous forms view, would be used, based on a query on the related table which returns rows in DateTimeStamp DESC order, i.e. the latest comment would be the first record in the subform.  Adding a new comment would simply be a question of inserting a new record into the subform.  In the subform's BeforeInsert event procedure the foreign key value would be inserted, and the DateTimeStamp column would be assigned a value with:

    Me.ID = Me.Parent.ID

    Me.DateTimeStamp = Now()

In the subform's AfterInsert event procedure the subform would be requeried with:

    Me.Requery

which would move the new record to the top of the subform.

I would, however, not use the generic column name ID as the primary and foreign key column names. Instead use a name which specifically identifies the entity type in question, e.g. TransactionID or similar.

Thank you. I had forgotten that method is now available.

https://learn.microsoft.com/en-us/office/vba/api/access.application.columnhistory

Please verify that this is the exact code in the control source in the original form and that it works as intended in that form.

=ColumnHistory([RecordSource],"Comments","[ID]=" & Nz([txtID],0))

That looks like a hybrid of an attempt at a function and a DLookup and, as such, should not work as is. But we don't know what it should be, unless it is intended to be a DLookup:

=DLookup("SomeFieldInTheCommentsTable", "Comments", "[ID] = " & Nz([txtID],0)

Thanks for clarifying the context.