A family of Microsoft relational database management systems designed for ease of use.
Since Notes is presumably a text field, you need to enclose what you're trying to insert in quotes:
"INSERT INTO tblFeedback (Notes) VALUES ('" & Me.txtbox_1 & "')"
In case it's not obviously, exagerated for clarity that's
" INSERT INTO tblFeedback (Notes) VALUES ( ' " & Me.txtbox_1 & " ' ) "
If there's a chance that there might be an apostrophe in what you're inserting, use the following instead:
"INSERT INTO tblFeedback (Notes) VALUES (""" & Me.txtbox_1 & """)"
(that's three double-quotes in a row)
If there's a chance that there might be double quotes in what you're inserting, use the following instead:
"INSERT INTO tblFeedback (Notes) VALUES ('" & Replace(Me.txtbox_1, "'", "''") & "')"
Again, exagerated for clarity, that's
" INSERT INTO tblFeedback (Notes) VALUES ( ' " & Replace(Me.txtbox_1, " ' ", " ' ' ") & " ' ) "