If your mobile phone and computer are connected to the same local network or router, you can enable file sharing on your PC, then connect iPhone to your PC to copy files between them. After that you need to download a SMB client app on mobile phone so you can connect to Windows SMB server to share files between computer and mobile device. We highly recommend this file explorer for iPhone. In this quick guide, we’d like to show you how to connect your iPhone to a Windows computer which has the File Sharing enabled so you can share files and documents between iPhone and PC over Wi-Fi.
Since iOS 13, the stock Files app is able to connect to SMB servers without the need for any third-party apps. Check out this guide to share files between iPhone iPad and computer via SMB.

Run the iPhone explorer app, then tap the Add (+ icon) button at the top right corner, you will see a list of all supported devices and connections.

Choose Windows from New Connection screen above, you will get a new screen like below. Other than manually input the Windows SMB server information, the file explorer can automatically detect your PC in the same local network. Scroll down to the bottom of the screen, you will see your PC name in the Network Neighborhood section. Tap on it, you can choose to connect as a registered user or guest.

Normally we do not recommend to enable the guest user account on your PC if you do not share the same PC with other people. Select Register User, then input your PC username and password to login your PC right on your iPhone. After the authentication, you will open your shared folders and files saved on Windows PC from your iPhone.
Share files and documents between iPhone and PC over Wi-Fi
Once your iPhone connect to Windows SMB share server, you can find the connection from the bottom of file explorer app on iPhone.
From the home page of the file explorer on iPhone, tap Local, Photo Library or iCloud Drive to select and copy files, the tap the Windows PC connection at the bottom of the file explorer to access shared folders on your Windows computer and paste the iPhone files to PC. Likewise, you can access the shared files and documents on PC, select and copy them, then open the target folder on iPhone to save them to.