Can I turn on Find My iPhone from my PC if I can't find my phone?

If Find my was already turned on, you can go to https://icloud.com/find on your pc to track, lock, or erase it.

If it was not already turned on before you lost it, it's too late to turn it on now.

Since the moderators changed the subject of your post, I don't know what your original question was.

terra458 wrote:

LOST MY PHONE NEED HELPFINDING IT

Find your lost iPhone or iPad - Apple Support

To answer your question........Can I turn on Find My iPhone from my PC if I can't find my phone?

The answer is no. To turn on Find My.....you must have the iPhone in your hands.

Unfortunately, the only way that you will be able to find your iPhone at this point is look for it with your eyes.

Re: “Unfortunately, the only way that you will be able to find your iPhone at this point is look for it with your eyes.”

If there is reason to think it is powered on and nearby (e.g. within one’s home), one could try calling it from another phone and listening for the sound of “ringing.”