https://www.epo.org/en/node/how-can-i-file

How can I file nucleotide and/or amino acid sequence listings in accordance with Annex C/WIPO Standard ST.26 text format as part of an international application?

Check the box The description contains a sequence listing in Biology on Form PCT/RO/101.

Go to Contents and select Sequence listing. Attach a sequence listing in accordance with WIPO Standard ST.26 format (XML or ZIP). 
Sequence listings in PDF format are not permitted under WIPO Standard ST.26.