During the request form / values block you could select between the following field types to request values from user.

Text, Textarea, Checkbox, Date

Default input elements. Nothing special

Picklist

Default picklist, with one special behavior. You could define label and an independent value for this selection, like in default HTML element.
To set a different value for a selection, add #~# and the value after the label. Then Workflow Designer will return this value for the selection.
For example with this function the configuration field looks like:

Fieldupload

This element show a simple field upload element and you need to define a Filestore ID, which should hold the path to the file and could be used in process.

Select Record

Here you could provide a record selector over all available records in a module. The records don’t need to be related to the current Record and you could define a condition to limit the available records, if you, for example, only want to provide the selection over “finance” companies.

Reference

Here you could provide a record selector over all records, which are related to the current one. For example to provide a selection about related Contacts in Organization.
Thie fieldtype is available only for compatibility reason, because most functions also could done by “Select Record”

Readonly Text

This type will only show a text to the User, if you would add a longer information, which should be confirmed, for example.