Very easy! This it what will happen if a customer pays in cash:
The customer orders in Glovo with the payment option to pay cash
You go to the pick up point and the app will inform the payment option chosen by the customer.
When delivering the order, you will receive the customers money.
Your cash balance increases and the system will take it into account in case you will need to pay at partners or to be able to withdrawn earnings in cash at the end of your booked slot.
The cash value you withdrawn, will be deducted from your next invoice.
A good idea could be to use a different wallet than your personal one in order to separate the money received from customers and avoid confusion.