Itunes can't find my device

The iPhone should appear as a small device button on the horizontal bar that goes across iTunes window. Here's a screenshot of my iTunes window (upper left corner) showing an iPod's device button (circled in red).

You don't see a device button for your iPhone when you connect it? If you do, click it to show the iPhone's settings screen in iTunes window. If you do not, try doing a Restart on the iPhone

Restart your iPhone, iPad, or iPod touch - Apple Support

You may want to also restart your Mac. If it's a MacBook, connect its power adapter so that it's not running on battery power. If other USB devices are connected, disconnect them.

Edit: Sorry... The link was wrong. I corrected it.

Please test after taking each of the steps below that you haven't already tried. Back up all data before making any changes.

1. If you're running any other application that connects to the device, such as (for example) Apple Configurator, quit it.

2. Follow the directions in this support article.

3. If you subscribe to iTunes Match, then on the device select

Settings ▹ iTunes & App Store ▹ iTunes Match: Off

Re-enable iTunes Match if the sync succeeds. (Credit for this solution to ASC member Blue Velvet.)

4. Take this step only if you're running OS X 10.9 ("Mavericks") or later. It moves to the Trash "semaphore" files that have not been cleaned up by the system and may be interfering with normal operation. The files are empty; they contain no data.

Please triple-click anywhere in the line below on this page to select it:

find L*/{Con*/*/Data/L*/,}Pref* -type f -size 0c -name *.plist.??????? -exec mv {} .Trash/ \; 2>&-

Copy the selected text to the Clipboard by pressing the key combination command-C.

Launch the built-in Terminal application in any of the following ways:

☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)

☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.

☞ Open LaunchPad and start typing the name.

Paste into the Terminal window by pressing the key combination command-V. I've tested these instructions only with the Safari web browser. If you use another browser, you may have to press the return key after pasting.

Wait for a new line ending in a dollar sign ($) to appear below what you entered.

Log out or restart the computer and empty the Trash.

5. As a last resort, restore the device in recovery mode.

iTunes should be able to connect to your iPhone regardless of its version, I'm running 12.4 as well and everything works flawlessly. Do your USB cable + iPhone connect to iTunes on other computers?

If not, I think your either your USB connector or your lightning port might be dusty or damaged.

If yes, then we are dealing with a software problem on your Mac (please reply if this is the case).