After placing a .png file into InDesign, can I edit the fill on the object and not just the background? When I apply a fill it only changes the background color.
Probably not. Generally, InDesign is not intended to edit raster (non-vector) files. Better edit your PNG in Photoshop then place it again in InDesign.
It's not really editing. It's more like using a grayscale/bitmap image as a mask for any of your InDesign swatches. Very useful for me to make sharp bitmap artwork in multiple spot colors. I don't know any other way actually. Mar 28, 2019 at 18:43
The only format that allows transparency and changing the image content color in a text editing program is a grayscale .tif.
Selecting the image.tif with the Selection Tool and clicking a color at the Swatches Panel the transparency get this color
Clicking the .tif content with the Selection Tool or the image.tif with the Direct Selection Tool and clicking a color at the Swatches Panel the image content get this color
Add after the comment: The image of this example is a transparent background grayscale mode .tif. If the grayscale image has more than a layer, when changing the content color, all the layers get the color applied as if they were merged.
1Actually it's not entirely true that the file has to be a grayscale .tif. This method could be used on both grayscale and bitmap images in .tif, .psd or .png format. Bitmap images are always flat but for grayscale images you need to make sure that the image is flattened. It can have layers on top of the background. Mar 28, 2019 at 18:38
1If you want to change the transparency color yes, but not for the content, it's what the OP is asking. In the image example, if the boy is in RGB or CMYK mode you can not change the color.– user120647Mar 28, 2019 at 18:55
1By "bitmap" i mean 1-bit images. I didn't mean RGB/CMYK images. Mar 28, 2019 at 20:57