You can follow these steps:
Website: On the dashboard (home page), click on the 3 dots beside the goal (you wish to hide/delete). You will see either an option called "Hide goal" or an option called "Delete goal".
App: Click on the goal (you wish to hide/delete) > Click on "More". You will see either an option called "Hide goal" or an option called "Delete goal".
If you have not made any transactions in this goal in the past, then you will get the option to Delete the goal. However, if there is any transaction history (even if you have now withdrawn the entire amount), then you will only get the option to Hide the goal.
This is because we cannot delete the transactions in the goal (deleting the goal will lead to deleting the transactions). All transactions are necessary for your Dashboard values and reports to be accurate. It's also an audit requirement to keep a record of all transactions.
If you wish to add any new goas, you can refer to this FAQ.