The tip is an amount that is freely adjusted at the end of the sale.

To enter the tip, we need to be on the payment method selection screen, once the ticket has been totaled. We select the box Tip alongside the selected payment method and add the corresponding amount (the next screen will appear if there is no suggested tip percentage in the terminal type configuration).

This option will be selectable if the option has been enabled in the payment method. Allow overpaid (and destination: Tip) in the section of Payment methodsor in Settings.
We will find its main configuration in the section of Settings, Terminal type, Tip

Even if the option to is enabled in the payment method Allow overpayment bound for Tip, if in the settings of Type of terminal Tip entry is not allowed; when finalizing a sale, we will not be able to add a tip manually. The reason for this is that the configuration reflected in the Terminal type is above the configuration of the Payment Method If desired, the tip can be applied automatically at checkout, and a percentage can be set for it. We can also configure up to three suggested tips.
In the event that in the Configuration, Type of terminal There are suggested tips configured, on the payment method selection screen, upon selecting Tip the following will be displayed:

The service charge, unlike the tip, is always applied to the total sale.
In Terminal type, from the menu Settings, we select whether we want to automatically apply a charge to the sale and what percentage to apply. It is advisable to determine whether to apply it before discounts and if it has an associated tax.

Additionally, there is the option that, starting from a certain number of diners, a second percentage is applied as a service charge, an option which can also be configured from Type of terminal.
This second service charge replaces the first type, and only the second applies.