To select a cause to benefit, simply click on the current cause at the top of the page.
Then, in the search field, search for and designate any nonprofit by name, EIN, or +Shop code.
Every +Shop also comes with a designated cause built in — so if you're shopping through a +Shop someone shared with you, your purchase supports their cause automatically. Nothing extra to select.
It's worth knowing... a nonprofit you designate yourself receives a 5% donation, while some registered +Shops earn higher rates.