Regardless of form, fabric softeners all work in the same manner. They mix scents with plant or animal surfactant that lie on the outside of your clothing to make them feel softer and smell better. If you use the dryer sheets, your clothes may have a waxy covering that softens them.
Fabric softeners make your clothes softer and smell better. They may also reduce the amount of wrinkles you have in your clothing and bedding.
Creators of fabric softeners do not have to list all ingredients and frequently list surfactants without including where they are derived from. They also sometimes include "amongst other ingredients" to mask the rest of the chemicals that are not disclosed on the label.
Fabric softeners function similar to hair conditioners and may irritate those with sensitive skin. It is also possible that fabric softeners impact health conditions, since people with sensitivities to smells or with asthma may have attacks with strong perfumes associated with softeners.
Fabric softeners reduce the absorbency of some materials with the waxy coating, specifically towels and cloth diapers, which impacts their functionality. If you use fabric softeners in your washing machine it may take several cycles to get the smell out of the machine and you may still be left with the chemicals softeners leave behind.