There are several ways to transfer files between iPhone and your computer or other iOS devices.

Transfer files using iTunes. Connect iPhone to your computer using the included cable. In iTunes on your computer, select iPhone, then click Apps. Use the File Sharing section to transfer documents between iPhone and your computer. Apps that support file sharing appear in the File Sharing Apps list in iTunes. To delete a file, select it in the Documents list, then press the Delete key.

You can also view files received as email attachments.

With some apps, you can transfer files using AirDrop.