This sample paper provides comprehensive information on how to format a paper in the APA Style:
SOURCE: American Psychological Association. (2020). Publication manual of the American Psychological Association (7th ed.). https://doi.org/10.1037/0000165-000
Appendices appear after your reference page and after your Footnote page (if applicable).
If your paper has one appendix, simply label it ‘Appendix;’ if it has more than one label each one with a capital letter (Appendix A, Appendix B, etc.)
Each appendix should be started on a separate page and the label (Appendix, Appendix A, etc.) should be centered on the top of the page.