Keepers are bots, scripts, other contracts, or simply EOA accounts that trigger events. This can be submitting a signed TX on behalf of a third party, calling a transaction at a specific time, or more complex functionality.
Each time you execute such a function, you are rewarded in either BNB, tokens, or the systems native token KPR. The maximum amount of KPR receivable is gasUsed + premium (configured by governance).
Jobs might require keepers that have a minimum amount of bonded tokens, have earned a minimum amount of fees, or have been in the system longer than a certain period of time.
At the most simple level, they simply require a keeper to be registered in the system.

Becoming a Keeper

To become a keeper, you simply need to call bond(address,uint), no funds are required to become a keeper, however certain jobs might require a minimum amount of funds.
* @notice begin the bonding process for a new keeper
* @param bonding the asset being bound
* @param amount the amount of bonding asset being bound
function bond(address bonding, uint amount) external
After waiting BOND days (default 3 days) and you can activate as a keeper;
* @notice allows a keeper to activate/register themselves after bonding
* @param bonding the asset being activated as bond collateral
function activate(address bonding) external

Removing a Keeper

If you no longer wish to participate you can unbond to deactivate.
* @notice begin the unbonding process to stop being a keeper
* @param bonding the asset being unbound
* @param amount allows for partial unbonding
function unbond(address bonding, uint amount) external
After waiting UNBOND days (default 14 days) you can withdraw any bonded assets
* @notice withdraw funds after unbonding has finished
* @param bonding the asset to withdraw from the bonding pool
function withdraw(address bonding) external

Additional Requirements

Some jobs might have additional requirements such as minimum bonded protocol tokens (for example SNX). In such cases you would need to bond a minimum amount of SNX before you may qualify for the job.