The PDF, or Portable Document Format, was designed as a reliable way to exchange documents independent of software, hardware or operating system. As such, it is has become a popular method of sharing a variety of documents, including photos. You can put your photos in a PDF and share them from the Photos app on your iPhone or iPad, though the feature is not at all obvious as it is found under "Print" in the sharing options. Here's how to put your photos in a PDF file and share it on iPhone or iPad:
Those who are signed up for Apple's Beta Software Program and testing iOS 12 may have noticed that it offers a new way to share photos - by sharing a direct link to your iCloud Photos that will last for 30 days. Not all features found in beta make it to the official iOS, but hopefully this one will, as it pretty useful for sending multiple photos. Instead of actually attaching each photo to an email or sending them in Messages, you are merely posting a link.
Sharing photos with friends and family is arguably the main reason people take photos in the first place. There are countless methods of sharing photos - you could share a folder of photos on Dropbox, upload to Facebook or Flickr, add to your story on Instagram, and the list goes on. Each has its own take on photo sharing and some may suit you better than others, but if you have an iPhone or iPad, iCloud Photo Sharing is an excellent option.
Whenever you tap the share button a two tiered "Activities" menu opens that gives you a variety of sharing options. Depending on what type of object you intend to share (photo, music, Notes, files, etc.), default options like AirDrop, Messages, Mail, AirPlay, Duplicate, Copy, etc. will come up. Some may not be aware, however, that the menu is customizable - you can add other options like Twitter, Facebook, Snapchat, Instagram, iCloud Drive, Dropbox and more. This makes sharing a lot easier than opening up individual apps and then accessing your photos/files in order to share them.