1: Open the picture and double-click the panel layer to unlock it.

2. Select the required part, and delete it after deselecting.

3. Save as gif, tif, png and other formats that support transparent graphics (in this way, you will still have a white background when you save it on your computer, but the background will be gone when you upload it to the network).

There are two key points: one is to unlock, and the other is to choose a format that allows transparency.