If your goal is to place a PHP file into the htdocs folder of another computer's XAMPP, here are your options:

Use File Sharing (SMB / Windows Share)

On the XAMPP host machine (the one running Apache/MySQL):

Share the htdocs directory:

Right-click C:\xampp\htdocs → Properties → Sharing → Share with specific people → Give your user read/write access.

From your development computer:

Open the shared folder via \\[IP address]\htdocs

Copy/edit PHP files directly.

Now you're directly modifying files that the XAMPP server will run.