I want to send photos by folders organized in the Photos app.

Yes. There are two ways.

In Send Anywhere app

1. On the Photo tab of the Send menu, click the More button(3 dots icon)
   in the upper right corner.
2. When you select an album, only the photos in that album folder are displayed.
3. Click the send button after selecting photos to send.

In Photos app (iOS native app)

1. Go to the folder you want.
2. Tap 'Select' button in the top right corner to switch to Select mode.
3. After you select the photos you want to send, tap Share icon button. then click Send Anywhere and send them.

* Please note that it is only possible to transfer via a 6-digit key or to-device, and if you turn off the screen before the transfer is completed, the transfer will be stopped.