These tasks are for the same project, in otherwords a website with an accompanying app. All source code is provided for both php and android and simply needs modified slightly and the android app compiled accordingly.
Add tax field and calculation
add additional field to selected page
make certain fields mandatory
compile android and make adjustments if necessary given the corresponding php modifications and rebrand (add given logo)
Completed job should have all suggested modifications in place and work as they should including but not limited to the android app interacting with the site and database as necessary.