If you put detergent instead of softener in the fabric softener compartment of the washing machine it will miss the wash cycle and the clothes won't wash properly.
The detergent would be released when the fabric softener should be released and the detergent residue would remain on the fabric.
You would have to run the clothes or laundry through another cycle with the detergent in the proper compartment or in the washing machine itself and wash the clothes over again to get the detergent out of the fabric.
Any remaining detergent that goes get flushed out will be mixed with water and sprayed on the clothing at the end of the next cycle during spin.
Worst case scenario is that you'll need to run another cycle if you get soap all over the clothing again at the end of the cycle instead of softener.
Unlike fabric softeners, you should never skip your detergent.
If you choose to wash a load without fabric softener, the laundry will still get washed properly it just won't be as soft.
However, if you skip your detergent, the softener alone won't get any dirt or bacteria out of your fabrics.
Although this can vary a little depending on the type of washing machine you have, or sometimes the type of liquid detergent you're using, more often than not liquid detergent works best when applied directly to clothes.
Fabric softener is completely optional, and your garments will likely pop out of the dryer feeling fresh, clean, and soft without.
However, “For some, it might make doing their laundry a little more fun to use an extra product that smells very good and is colorful.
Laundry detergent helps remove dirt and grime from your clothes, while fabric softener is designed to protect and strengthen your clothing during the wash cycle so that it retains its natural shape.