please cropp 21 simple Ilustrations and convert to cmyk for print

You get 21 illustrations, they are in rgb and in .png format. Please convert all illustrations to cmyk. I would like to print the illustrations in 4 color offset. Please create a clipping path in Photoshop and send me the illustrations in a format that I can use to insert the cropped illustration into InDesign.
Iam not sure if the format will be tiff oder eps?