how to put photos from iPhone onto your mac

You import them. See this support document. Import photos and videos from your iPhone, iPad, or iPod touch to your Mac or Windows PC - Apple Support

This support document is not helpful. It does not tell you the steps by which you can actually transfer photographs or videos on your iPhone to your Mac.
I've the same query, kindly guide.

This is from that support document.

Import photos and videos to your Mac

You can use Photos or Image Capture to import media from your iOS device. After you import, you can edit your photos and videos. You can also trim video clips, put together photo books, and more.

After you import your photos from your iOS device to your computer, you can use iTunes to sync them back to your device. You can't import photos or videos synced from iTunes. You can only import photos and videos from the Camera Roll on your device.

Photos and Image Capture

If you have photos or videos saved on a hard disk or other storage device, you can import them to Photos on your Mac.

If you have photos that were taken with a film camera, you can import them to Photos by converting them to digital files with a scanner. You can also change the date and time of the scanned images in Photos. Select the image and choose Image > Adjust Date and Time.

Learn more about using Image Capture to import images.

There are two different links contained in the document that describe what to do, depending on what program you are using on the Mac to import the photos. You would need to determine that.

Thanks for the reply Chris.

I've read this document. the problem is as follows:

I have "Photos" app on my mac but there seems no way to transfer photographs on my iPhone to my mac using this app. If the app is supposed to detect my phone connected to mac, it is not doing that.

Can you help me out?

I'm not a Mac user, so I'm not familiar with Photos, but this support document linked in what I sent earlier discusses Photos. Photos for OS X: Import photos and video from storage media

If you are having issues with the Mac recognizing the iPhone, then see this support document. If you don't see your connected device in iTunes for Mac - Apple Support

Or you will need to wait for a Mac user to read this and try to help.