Hi,
That is the correct icon for the Transform node. The node icon was changed a while ago to represent a stylized 'T' in a data grid. The Transform node is a general-purpose node that can perform a wide variety of transformation tasks, of which filtering is only one aspect.
There is a dedicated Filter node which offers script-free configuration of the filter criteria. This node uses a stylized funnel as its icon. A pre-configured Filter node can also be automatically added to the canvas when a filter is applied to data displayed in the Data Viewer.

The online documentation for the Transform node is available in the help. It is also available online here:
https://d3sa-preview.infogixsaas.com/docs/dist/help/Default.htm#e-node-help/Aggregation_and_Transformation/transform.html
The Filter node documentation is also available in the help and online here:
https://d3sa-preview.infogixsaas.com/docs/dist/help/Default.htm#e-node-help/Aggregation_and_Transformation/filter.html
You may also want to review the information at the start of the following knowledgebase article, which overviews the use of the Filter node.
Regards,
Adrian