Holding has to do with buying your coins and keeping it in your wallet without having to do anything but just wait for the market to give you a percentage increase you are comfortable with then you sell. Holding are foe people who do not want to trade and keep to date with development of the project they invested in  Holding should be done only in private wallet and not done on exchange or wallet you do not own your private key.

Staking is holding 2.0. with staking you do everything a holder does but now your holdings give you passive income as they make more money for you instead of staying dominate. Staking has its disadvantages as most coins with that feature gets dumped easily so you have to be very careful when choosing a project you want to hold and stake.