Currently, there's no option to receive payments from all of your customers in one step or in bulk. You can only perform receive payment to each customer with all their invoices.
Here's how:
Choose + New at the left panel.
Select Receive Payment.
Select the name of the customer from the drop-down menu.
Select your payment method.
Enter the Reference no. and Memo if applicable.
Under Amount Received, enter the amount of the payment.
From the Outstanding Transactions section, select the invoices you want to apply the payment to by putting a checkmark in the boxes.