You cannot transfer money worldwide using Venmo. The company only supports domestic transfers in the US. Maybe in the future, Venmo will go global just like the parent PayPal and other payment platforms such as Payoneer, Google Pay, Skrill, and others. International money transfer helps companies to pay their remote employees in other countries easily.
If you have money in your Venmo account and would like to send it to someone in another country, you can simply transfer the money to your bank account, then transfer it to your PayPal account or any other relevant payment wallet such as Payoneer. Sending money with PayPal and Payoneer is instant although recipients will have to wait for around 1-5 days for the money to reflect in their bank accounts once they initiate the withdrawal.
The time taken to wait depends on the bank you are transferring the money to. Also, there are charges involved when transferring money to your bank account. PayPal and Payoneer mostly convert the money to transfer at a lower rate as compared to the prevailing exchange rates to cater to the transaction fees. This is a tricky way to make users believe that the transaction is free when in a real sense it is not.