Tezos is a PoS (Proof of Stake) based platform that allows you to participate in the validation of transactions and rewards users monthly. Tezos holders can stake their coins and receive Tezos tokens as a reward. Validators (Bakers) produce blocks and users can delegate their funds to Bakers. Each month, the Baker sends a reward for staking to users.
How to stake XTZ on Guarda
Open your Tezos wallet on Guarda and press 'staking', then 'Deposit for staking'
Select a baker in "To" field. You can choose a baker, depending on the minimum amount required by the baker and the amount of reward. You can send only the entire balance. But the funds are not frozen and you can send them anytime.