An Apostille must be placed directly on the public document itself or on a separate attached page (called an allonge). Apostilles may be affixed by various means, including rubber stamps, self-adhesive stickers, impressed seals, etc.
If an Apostille is placed on an allonge, the latter can be attached to the underlying public document by a variety of means, including glue, grommets, staples, ribbons, wax seals, etc. While all of these means are acceptable under the Convention, Competent Authorities are encouraged to use more secure methods of affixation so as to safeguard the integrity of the Apostille.
Failure to affix an Apostille in a particular manner is not a basis for refusing the Apostille.