Soft Cap - Minimum fund required for the project/ICO to proceed. If the Softcap is not achieved, the project will not move any further and the investments will be returned to the investors.
Hard Cap - Maximum Fund required for the project/ICO. If the project raised the Hardcap, the Crowdsale will automatically close and the development process starts right away.
For instance, let's see VRT world, This ICO has a soft cap around 3.5 million and a hard cap of 16 million. This means that if the project does not attain 3.5 million it will not proceed and also if it reaches 16 million no more can be contributed.