A square image can work for a product card, a social tile or a profile source, but the shape itself does not guarantee a strong composition. Look at the original and identify the content that must remain visible. A centered object may fit naturally, while a wide group portrait may require losing people at the sides. Do not approve the shape before checking those consequences.
This preset uses 1080 by 1080 pixels as an export example, not a requirement for every website or social service. Check the destination's current instructions when it has a specific size or byte limit. If the full rectangular photo must remain visible, use Fit within instead. That keeps the source ratio and does not create a square by adding borders. The cropper cannot extend the background or rearrange objects to make a difficult composition fit.