The Share Sheet is allows you to send the content you are currently looking at (a photo, a web page, a document, a voicemail, etc.) to another app. To get started tap the Share button which is available on most screens where you are looking at content. If a large number of apps can accept the shared item, you might have to scroll to the right quite a bit to get to the icon you want. For occasional use, that’s fine, but there’s no need to scroll each time, since you can rearrange the Share sheet icons. Just touch and hold on the one you want to move, and then drag it right or left, lifting your finger to drop it in place. This trick works for each row in the sheet. Next time you’re in a Share sheet, take a moment to customize it the way you want.
You can also scroll to the last item, “More” to bring up a panel to turn items on or off, or rearrange them by dragging up or down using the little grippy icon to the right. When you are finished tap the “Done” button in the upper right corner.