This code will create a table description and field descriptions:
Dim db As DAO.Database
Dim prp As DAO.Property
Dim tbl As DAO.TableDef
Dim fld As DAO.Field
Dim i As Integer
Set db = CurrentDb()
i = 1
Set tbl = db.TableDefs(TableName)
Set prp = tbl.CreateProperty("description", dbText)
prp.Value = "Table to illustrate setting descriptions"
tbl.Properties.Append prp
For Each fld In tbl.Fields
Set prp = tbl.CreateProperty("description", dbText)
prp.Value = "Field " & i & " of the " & TableName & " table"
fld.Properties.Append prp
i = i + 1
Next
Now, this will only work for tables and fields which do not already have
descriptions. You will need to error trap for those that do have
description and instead fo using the CreateProperty method, you would use
the Properties method to set the value.
And of course, the table and field descriptions set here are just for
illustration.