You can execute DDL queries via ADO or DAO, or you can use the DAO or ADOX
object models ...
Public Sub AddRemoveCols()
'execute DDL query via ADO
CurrentProject.Connection.Execute _
"ALTER TABLE tblTest DROP Column TestText", , adCmdText
'execute DDL query via DAO
CurrentDb.Execute _
"ALTER TABLE tblTest ADD Column TestText TEXT (25)", dbFailOnError
'use DAO object model
CurrentDb.TableDefs("tblTest").Fields.Delete ("TestText")
'use ADOX object model
Dim cat As ADOX.Catalog
Set cat = New ADOX.Catalog
Set cat.ActiveConnection = CurrentProject.Connection
cat.Tables("tblTest").Columns.Append "TestText", adVarWChar, 30
End Sub