How to create fixed format of data input

What is a mask, how to set it up, what it is needed for.
To format the data that people send via a form, you need to add a mask.
It allows a user to more easily enter data in a certain format (dates, phone numbers, etc.).
A mask is defined by a format made up of mask literals and mask definitions. Any character not in the definitions list below is considered a mask literal. Mask literals will be automatically entered for the user as they type and will not be able to be removed by the user.

To make a mask open block Content menu, add a field with the value 'One line input field' and put data format (mask):
How to create a mask:

a — Represents an alpha character (A-Z,a-z)
9 — Represents a numeric character (0-9)
* — Represents an alphanumeric character (A-Z,a-z,0-9)

Date: 99/99/9999
Phone: (999) 999-9999
Card number: 9999-9999-9999-9999
A mask defines the type of symbol and its quantity. If you need less strong checking, for instance, helping people with entering numbers in a phone field and letters in a name field, use a validation rule. Validation rule allows checking to ensure input date type (letters in Name field, numbers in Phone field etc.)
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