The documentation for versions 2.21 and older can be found here.
On this page
How many field types exist?
Currently, thirteen field types exist.
Those field types are:
Text input
Multiline text
Select
Multi select
Cascade select
Date input (old)
Date input (new)
User select
Phone number
Instant Messenger
Language select
Country select
Retrieved from LDAP
Dependent field
Why should I use the profile field type Multiline text ?
It allows users to enter text. Users can also use line breaks and create lists. It's just a bigger text field which is not limited to a single line. It's a great field type for a short user introduction.
The multiline text also allows users to enter links. Those links will become clickable.
Special configuration
How to use line breaks in Multiline text when syncing via XML
As the name suggests, the Multiline text field type offers the ability to store multiple lines of text in a profile field. If you wish to use this profile field via XML, here's what you need to consider: